Why is quicksort better than other sorting algorithms ?

The following counts of compare and exchange operations were made for three different sorting algorithms running on the same data:

n	Quick		Heap		Insert
	Comparison	Exchange	Comparison	Exchange	Comparison	Exchange
100	712	148	2,842	581	2,595	899
200	1,682	328	9,736	1,366	10,307	3,503
500	5,102	919	53,113	4,042	62,746	21,083

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c assignment 6

↓↑ Program to implement binary Search. 

#include<stdio.h>
int main()
{
 int low,high,mid,i,a[15],key,n;
 printf("Enter No  in array in sorted order:");
 scanf("%d",&n);
 for(i=0;i<n;i++)
  scanf("%d",&a[i]);

 low=0;
 high=n-1;
 printf("\nenter key to be searched:");
 scanf("%d",&key);
 for(i=0;i<n;i++)
 { 
  mid=(low+high)/2;
  if(a[mid]==key)
  {
   printf("element fount at %d position\n",mid+1); 
   break;
  }
   
  if(a[mid]<key)
   low=mid+1;
  if(a[mid]>key)
   high=mid-1;
  
 }
return 0;
}


↓↑ Program to implement bubble sort. 

#include<stdio.h>
#define MAX 15
int main()
{
 int a[MAX],i,temp,j,n;
 printf("enter the no of element:");
 scanf("%d",&n);
 for(i=0;i<n;i++)
  scanf("%d",&a[i]);
 for(i=0;i<n;i++)
 {
  for(j=0;j<n-1-i;j++)
  {
   if(a[j]>a[j+1])
   {
    temp=a[j+1];
    a[j+1]=a[j];
    a[j]=temp;
   }
  }
 }
printf("sorted array is:");
for(i=0;i<n;i++)
printf("%d\t",a[i]);
printf("\n");
return 0;
}


↓↑ Program to implement circular queue.

#include<stdio.h>
#define MAXSIZE 5
int cq[10];
int front=-1,rear=0;
int choice;
char ch;
void main()
{

do
{

    printf("1.Insert-------\n");
    printf("2. Delete------\n");
    printf("3. Display-----\n");
    printf("4.exit---------\n");
    printf("Enter your choice:");
    scanf("%d",&choice);
    switch(choice)
    {
        case 1 : cqinsert();
        break;
        case 2 : cqdelete();
        break;
        case 3 : cqdisplay();
        break;
        case 4: return;
    }
        fflush(stdin);
}while(choice!=4);

}
cqinsert()
{
    int num;
    if(front==(rear+1)%MAXSIZE)
    {
        printf("Queue is full\n");
        return;
    }
    else
    {
        printf("Enter the element to be inserted\n");
        scanf("%d",&num);
        if(front==-1)
            front=rear=0;
        else
            rear=(rear+1) % MAXSIZE;
        cq[rear]= num;
    }
    return;
}

int cqdelete()
{
    int num;
    if(front==-1)
    {
        printf("Queue is Empty\n");
        return;
    }
    else
    {
        num=cq[front];
        printf("Deleted element is =%d\n",cq[front]);
        if(front==rear)
            front=rear=-1;
        else
            front=(front+1)%MAXSIZE;
    }
     return(num);
}

cqdisplay()
{
    int i;
    if(front==-1)
    {
        printf("Queue is empty\n");
        return;
    }
    else
    {
        printf("\nThe status of the queue\n");
        for(i=front;i<=rear;i++)
        {
            printf("%d\n",cq[i]);
        }
    }
    if(front>rear)
    {
        for(i=front;i<MAXSIZE;i++)
        {
            printf("%d\n",cq[i]);
        }
        for(i=0;i<=rear;i++)
        {
            printf("%d\n",cq[i]);
        }
    }
printf("\n");
}


↓↑ Program to implement infix to postfix expression.

#include<stdio.h>
#include<string.h>
char stack[50];
int top=-1;
void in_to_post(char infix[]);
void push (char);
char pop();
int main()
{
    char infx[25];
    printf("Enter the infix expression");
    gets(infx);
    in_to_post(infx);
return 0;
}

void push (char symb)
{
    if (top>=49)
    {
     printf("stack overflow");
        return;
    }
    else
    {
     top=top+1;
     stack[top]=symb;
    }
}

char pop()
{
    char item;
    if(top==-1)
    {
     printf("stack empty");
 return(0);
    }
    else
    {
     item=stack[top];
     top--;
    }
return(item);
}

int preced(char ch)
{
    if(ch==47)
    {
     return(5);
    }
    else
    if(ch==42)
    {
     return(4);
    }
    else if(ch==43)
    {
     return(3);
    }
    else
return(2);
}
void in_to_post(char infix[])
{
    int length;
    static int index=0,pos=0;
    char symbol,temp;
    char postfix[40];
    length=strlen(infix);
    push('#');
    while(index<length)
    {
     symbol=infix[index];
     switch(symbol)
     {
      case'(':push(symbol);
       break;
      case')' :temp=pop();
      while(temp!='(')
      {
       postfix[pos]=temp;
       pos++;
       temp=pop();
      }
      break;
      case '+' :
      case '-' :
      case '*' :
      case '/' :
      case '^' :
      while (preced(stack[top])>=preced(symbol))
      {
       temp=pop();
       postfix[pos]=temp;
       pos++;
      }
      push(symbol);
      break;
      default : postfix[pos++]=symbol;
       break;
     }
    index++;
    }
    while(top>0)
    {
        temp=pop();
 postfix[pos++]=temp;
    }
    postfix[pos++]='\0';
    puts(postfix);
    return;
}


↓↑ Program to implement insertion sort. 

#include<stdio.h>
int main()
{
 int a[15],i,k,key,n;
 printf("enter no of element in  array n=:");
 scanf("%d",&n);
 printf("enter array element:");
 
 for(i=0;i<n;i++)
 { 
   scanf("%d",&a[i]);
 }
 
 for(k=1;k<n;k++)
 {
  key=a[k];
  for(i=k-1;key<a[i]&&i>=0;i--)
  {
   a[i+1]=a[i];
  }
 a[i+1]=key; 
 }
 printf("sorted array is::");
 for(i=0;i<n;i++)
 printf("%d\t",a[i]);

printf("\n");
return 0;
}


↓↑ Program to implement linear search. 

#include<stdio.h>
#define MAX 15
int main()
{
 int a[MAX],i,n,item,flag=0,pos;
 printf("enter how many element you want to enter:");
 scanf("%d",&n);
 for(i=0;i<n;i++)
 {
 scanf("%d",&a[i]);
 } 
 printf("\nenter item to be searched:");
 scanf("%d",&item);
 for(i=0;i<n;i++)
 {
  if(item==a[i])
  {
    flag=1;
   pos=i;
   break;
  }
 }
 if(flag==1) 
 printf("item found at %d position\n",pos);
 else
 printf("item not found\n");
return 0;
}



↓↑ Program to implement merge sort. 

#include<stdio.h>
#define MAX 50

void mergeSort(int arr[],int low,int mid,int high);
void partition(int arr[],int low,int high);

int main(){

    int merge[MAX],i,n;

    printf("Enter the total number of elements: ");
    scanf("%d",&n);

    printf("Enter the elements which to be sort: ");
    for(i=0;i<n;i++){
         scanf("%d",&merge[i]);
    }

    partition(merge,0,n-1);

    printf("After merge sorting elements are: ");
    for(i=0;i<n;i++){
         printf("%d ",merge[i]);
    }

   return 0;
}

void partition(int arr[],int low,int high){

    int mid;

    if(low<high){
         mid=(low+high)/2;
         partition(arr,low,mid);
         partition(arr,mid+1,high);
         mergeSort(arr,low,mid,high);
    }
}

void mergeSort(int arr[],int low,int mid,int high){

    int i,m,k,l,temp[MAX];

    l=low;
    i=low;
    m=mid+1;

    while((l<=mid)&&(m<=high)){

         if(arr[l]<=arr[m]){
             temp[i]=arr[l];
             l++;
         }
         else{
             temp[i]=arr[m];
             m++;
         }
         i++;
    }

    if(l>mid){
         for(k=m;k<=high;k++){
             temp[i]=arr[k];
             i++;
         }
    }
    else{
         for(k=l;k<=mid;k++){
             temp[i]=arr[k];
             i++;
         }
    }

    for(k=low;k<=high;k++){
         arr[k]=temp[k];
    }
}


↓↑ Program to evaluate postfix expression. 

#include<stdio.h>
#include<math.h>
float stack[10];
int top=-1;
void push(char);
float pop();
float eval(char [],float[]);
int main()
{
    int i=0;
    char suffix[20];
    float value[20],result;
    printf("Enter a valid postfix expression:");
    gets(suffix);
    while (suffix[i]!='\0')
    {   
     if(isalpha(suffix[i]))
     {
         fflush(stdin);
         printf("\nEnter the value of %c",suffix[i]);
         scanf("%f",&value[i]);
     }
        i++;
    }
    result=eval(suffix,value);
    printf("The result of %s=%f",suffix,result);
return 0;
}

float eval(char suffix[],float data[])
{
    int i=0;
    float op1,op2,res;
    char ch;
    while(suffix[i]!='\0')
    {
     ch=suffix[i];
     if(isalpha(suffix[i]))
     {
            push(data[i]);
     }
     else
     {
            op2=pop();
     op1=pop();
     switch(ch)
     {
         case '+' : push(op1+op2);
  break;
  case '-' : push(op1-op2);
  break;
  case '*' : push(op1*op2);
  break;
  case '/' :push(op1/op2);
  break;
  case '^' : push(pow(op1,op2));
  break;
            }
        }
    i++;
    }
    res=pop();
return(res);
}
void push(char num)
{
    top=top+1;
    stack[top]=num;
}
float pop()
{
    float num;
    num=stack[top];
    top=top-1;
return(num);
}



↓↑ Program to implement queue.

#include<stdio.h>
#define MAXSIZE 5
int front=-1, rear=-1,choice;
int q[10];
void qinsert();
void qdelete();
void qdisplay();
int main()
{
do
{
    printf("\n1-->insert\n");
    printf("2-->delete\n");
    printf("3-->display\n");
    printf("4-->exit\n");
    printf("enter your choice:");
    scanf("%d",&choice);
    switch(choice)
    {
        case 1:qinsert();
            break;
        case 2:qdelete();
            break;
        case 3:qdisplay();
            break;
        case 4:break;
    }
}while(choice!=4);
return 0;
}
void qinsert()
{
    int num;
    if(rear==(MAXSIZE-1))
    {
        printf("queue is full\n");
    return;
    }
    else
    {
        printf("enter no\n");
        scanf("%d",&num);
        rear=rear+1;
        q[rear]=num;
        if(front==-1)
        {
            front++;
        }
    }
 return;
 }
void qdelete()
{
    int num;
    if(front==-1)
    {
        printf("queue empty\n");
    return;
    }
    else
    {
    if(front==rear)
        front=rear=-1;
    else
    {
        num=q[front];
        printf("deleted item=%d",q[front]);
        front++;
    }
}
//return(num);
}
void qdisplay()
{
    int i;
    if(front==-1)
    {
        printf("queue empty\n");
    return;
    }
    else
    {
        printf("\nThe status of the queu\n");
        for(i=front;i<=rear;i++)
        {
            printf("%d\t",q[i]);
        }
    }
    printf("\n");
}


↓↑ Program to implement Quicksort. 

#include<stdio.h>
void quick(int a[],int,int);
int partition(int a[],int,int);
int main()
{
    int a[15],i,lb,hb,n;
    printf("enter no of element in array :");
    scanf("%d",&n);
    printf("enter element:");
    for(i=0;i<n;i++)
    scanf("%d",&a[i]);
    lb=0;
    hb=n-1;
    quick(a,lb,hb);
    printf("sorted array after quick sort:");
    for(i=0;i<n;i++)
    {
     printf("%d\t",a[i]);
    }
return 0;
}

void quick(int a[],int lb,int ub)
{
    int pos;
    if(lb>=ub)return;
    pos=partition(a,lb,ub);
    quick(a,lb,pos-1);
    quick(a,pos+1,ub);
}
int partition(int a[],int l,int h)
{
    int pivot,down,up,pos,temp;
    pivot=a[l];
    down=l;
    up=h;
    do
    { 
        while(pivot>=a[down])
     down++;
 while(pivot<a[up])
     up--;
 if(down<up)
 {
     temp=a[down];
     a[down]=a[up];
     a[up]=temp;
 }
    }while(down<up);

    pos=up;
    a[l]=a[pos];
    a[pos]=pivot;
return pos;
}





↓↑ Program to implement selection sort. 

#include<stdio.h>
int main()
{
    int a[15],i,j,min,n,minpos,temp;
    printf("enter no of element:");
    scanf("%d",&n);
    printf("\nenter array element:");
    for(i=0;i<n;i++)
    scanf("%d",&a[i]);
    min=a[0];
    for(i=0;i<n;i++)
    {
        min=a[i];
 minpos=i;
 for(j=i+1;j<n;j++)
 {
            if(a[j]<min)
     {
         min=a[j];
  minpos=j;
     }
            if(minpos!=i)
     {
         temp=a[i];
  a[i]=a[minpos];
  a[minpos]=temp;
            }  
 }
    }
    printf("\nsorted array is:");
    for(i=0;i<n;i++)
        printf("%d\t",a[i]);

    printf("\n");
return 0;
}


↓↑ Proram to implement stack. 

#include<stdio.h>
#include<stdlib.h>
#define MAX 10
struct student;
void push(struct student *,int);
int pop(struct student *);
void display(struct student *);
struct student
{
    int arr[MAX];
    int top;  
};
typedef struct student *ps;    
struct student s1;
int main()
{

    int n,choice;
    char ch;
    s1.top=-1;
    do{
        printf("\n1.push\n2.pop\n3.display\n0.exit\nenter choice:");
 scanf("%d",&choice);
 switch(choice)
 {
     case 1:
      printf("enter value :");
      scanf("%d",&n);
      push(&s1,n); 
     break;
     case 2:
         n=pop(&s1);
  if(n==-1)
  {
      printf("stack is empty\n");
  }
  else
      printf("popped value is:%d \n",n);
     break;
     case 3:
         display(&s1);
     break;

            case 0:
      exit(0);
     default: 
         printf("invalid choice!!!!\n");
 }
    }while(1);

return 0;
}
void push(ps p,int n)
{
    if(s1.top==MAX-1)
    printf("stack overflow\n");
    else
    p->arr[++p->top]=n;
}

int pop(ps p)
{
    if(p->top==-1)
    {
        printf("stack underflow!!!\n");
        return;
    }
return (p->arr[(p->top)--]);
}

void display(ps p)
{
    int i;

    for(i=p->top;i>=0;i--)
    {
        printf("%d ",p->arr[i]);
    }
    printf("\n");
}



↓↑ Program to implement tower of hanoi. 

#include<stdio.h>
void move(int,char,char,char);
int k=0;
int main()
{
    int n;
    printf("enter no of disc's:");
    scanf("%d",&n);
    move(n,'A','C','B');
    printf("total moves =%d\n",k);
return 0;
}

void move(int n,char src,char dest,char mid)
{
    if(n==0)
     return;
    move(n-1,src,mid,dest);
    printf("move %d from %c\n",n,src,dest);
    k++;
    move(n-1,mid,dest,src);
}


↓↑ Program to implement Binary search tree,inorder,preorder,postorder traversal. 

#include<stdio.h>
#include<malloc.h>
struct bt
{
    struct bt *left;
    int data;
    struct bt *right;
};
typedef struct bt snode;
typedef struct bt* psnode;
void insert(int);
void inorder(psnode);
void preorder(psnode);
void postorder(psnode);
int search(int);
psnode root=NULL;

int main()
{
    int ch,n;
    do 
    { 
     printf("1.insert.\n2.inorder\n3.preorder\n4.postorder\n5.search element.\n6.exit.\nenter chioce:"); 
     scanf("%d",&ch);
     switch(ch)
     {
         case 1:printf("\nenter the element to insert:");
                scanf("%d",&n);
  insert(n);
     break;
     case 2:inorder(root); printf("\n"); break;
     case 3:preorder(root);printf("\n");  break;
     case 4:postorder(root);printf("\n"); break;
     case 5:printf("enter element to search:");
         scanf("%d",&n);
  search(n);
     break;   
     case 6:break;
     default: printf("wrong choice!!!!!\n");
 }
    }while(ch!=6);
return 0;
}

void insert(int n)
{
    psnode ptr1,ptr,prev;
    ptr=(psnode)malloc(sizeof(struct bt));
    ptr->data=n;
    ptr->left=ptr->right=NULL;
    if(root==NULL)
    {
     root=ptr;return;
    }
    else
    {
        ptr1=root;
        prev=NULL;
        while(ptr1)
        {
            prev=ptr1;
            if(n< ptr1->data)
     {
         ptr1=ptr1->left;
     }
     else if(n > ptr1->data)
     {
         ptr1=ptr1->right;  
     }
        }  
        if(n>prev->data) prev->right=ptr;
        if(n<prev->data) prev->left=ptr;
    }
}

void inorder(psnode p)
{
    if(p==NULL) return; 
    inorder(p->left);
    printf("%d ",p->data); 
    inorder(p->right);
}

void preorder(psnode p)
{
    if(p==NULL)return;
    printf("%d ",p->data);
    preorder(p->left);
    preorder(p->right);
}
void postorder(psnode p)
{
    if(p==NULL)return;
    postorder(p->left);
    postorder(p->right);
    printf("%d ",p->data);
}

int search(int key)
{
    psnode ptr=root;
    while(ptr)
    {
     if(key==ptr->data)
     { 
            printf("element found.\n"); return 1;
        }
        else if(key<ptr->data)
     ptr=ptr->left;
        else
     ptr=ptr->right; 
    }
    printf("\nnot found\n");
return 0;
}


↓↑ Program for Dijkstra's single source shortest path algorithm. 

 
#include <stdio.h>
#include <limits.h>
#include <stdbool.h> 
// Number of vertices in the graph
#define V 9
 
// A utility function to find the vertex with minimum distance value, from
// the set of vertices not yet included in shortest path tree
int minDistance(int dist[], bool sptSet[])
{
    int v;
   // Initialize min value
    int min = INT_MAX, min_index;
 
    for (v = 0; v < V; v++)
        if (sptSet[v] == false && dist[v] <= min)
            min = dist[v], min_index = v;
    return min_index;
}
 
// A utility function to print the constructed distance array
int printSolution(int dist[], int n)
{
    int i;
    printf("Vertex   Distance from Source\n");
    for (i = 0; i < V; i++)
        printf("%d \t\t %d\n", i, dist[i]);
}
 
// Funtion that implements Dijkstra's single source shortest path algorithm
// for a graph represented using adjacency matrix representation
void dijkstra(int graph[V][V], int src)
{
     int i,count,v;
     int dist[V];     // The output array.  dist[i] will hold the shortest
                      // distance from src to i
 
     bool sptSet[V]; // sptSet[i] will true if vertex i is included in shortest
                     // path tree or shortest distance from src to i is finalized
 
     // Initialize all distances as INFINITE and stpSet[] as false
     for (i = 0; i < V; i++)
        dist[i] = INT_MAX, sptSet[i] = false;
 
     // Distance of source vertex from itself is always 0
     dist[src] = 0;
 
     // Find shortest path for all vertices
     for (count = 0; count < V-1; count++)
     {
       // Pick the minimum distance vertex from the set of vertices not
       // yet processed. u is always equal to src in first iteration.
       int u = minDistance(dist, sptSet);
 
       // Mark the picked vertex as processed
       sptSet[u] = true;
 
       // Update dist value of the adjacent vertices of the picked vertex.
       for (v = 0; v < V; v++)
 
         // Update dist[v] only if is not in sptSet, there is an edge from 
         // u to v, and total weight of path from src to  v through u is 
         // smaller than current value of dist[v]
         if (!sptSet[v] && graph[u][v] && dist[u] != INT_MAX 
                                       && dist[u]+graph[u][v] < dist[v])
            dist[v] = dist[u] + graph[u][v];
     }
 
     // print the constructed distance array
     printSolution(dist, V);
}
 
// driver program to test above function
int main()
{
   
   int graph[V][V] = {{0, 4, 0, 0, 0, 0, 0, 8, 0},
                      {4, 0, 8, 0, 0, 0, 0, 11, 0},
                      {0, 8, 0, 7, 0, 4, 0, 0, 2},
                      {0, 0, 7, 0, 9, 14, 0, 0, 0},
                      {0, 0, 0, 9, 0, 10, 0, 0, 0},
                      {0, 0, 4, 0, 10, 0, 2, 0, 0},
                      {0, 0, 0, 14, 0, 2, 0, 1, 6},
                      {8, 11, 0, 0, 0, 0, 1, 0, 7},
                      {0, 0, 2, 0, 0, 0, 6, 7, 0}
                     };
 
    dijkstra(graph, 0);
 
    return 0;
}


↓↑ Program to implement Heap sort. 

#include<stdio.h>
int a[15],n;
void del_root(int);
void heap_sort();
void insert(int,int);
void create_heap();

int main()
{
    int i;
    printf("Enter the No. of Elements\n");
    scanf("%d",&n);
  
    for(i=0;i<n;i++)
    {
        printf("Enter the %d Element\n",i+1);
        scanf("%d",&a[i]);
    }

    printf("\nEntered list is:");
    for(i=0;i<n;i++)
    {
        printf("%d\t",a[i]);
    }
    create_heap();
    printf("\nHeap is:");
    for(i=0;i<n;i++)
    {
        printf("%d\t",a[i]);
    }
    heap_sort();
    printf("\nSorted list is:");
  
    for(i=0;i<n;i++)
    {
        printf("%d\t",a[i]);
    }
    printf("\n");
return 0;
}

void del_root(int last)
{
    int left,right,i,temp;
    i=0;
    temp=a[i];
    a[i]=a[last];
    a[last]=temp;
  
    left=2*i+1;
    right=2*i+2;
  
    while(right<last)
    {
        if((a[i]>=a[left])&&(a[i]>=a[right]))
            return;
    
        if(a[right]<=a[left])
        {
            temp=a[i];
            a[i]=a[left];
            a[left]=temp;
            i=left;
        }
        else
        {  
            temp=a[i];
            a[i]=a[right];
            a[right]=temp;
            i=right;
        }
    
        left=2*i+1;
       right=2*i+1;
    }
    if((left==last-1)&&a[i]<a[left])
    {
        temp=a[i];
        a[i]=a[left];
        a[left]=temp;
    }
}

void heap_sort()
{
    int i=n-1;
  
    for(;i>0;i--)
    {
        del_root(i);
    }
}



void insert(int num,int loc)
{
    int parent;
    while(loc>0)
    {
        parent=(loc-1)/2;
        if(num<=a[parent])
        {
            a[loc]=num;
            return;
        }
        a[loc]=a[parent];
        loc=parent;
    }
  
    a[0]=num;
}


void create_heap()
{
    int i;
    for(i=0;i<n;i++)
    {
        insert(a[i],i);    
    }
}



↓↑ link list which makes two other list one with no's divisible by 3  other with rest 

   
#include<stdio.h>
#include<malloc.h>

struct node{
        int data;
        struct node *next;
};

struct node *start,*start1,*start2;
void display();
void create(int);
void displaydiv3();
void displaynotdiv3();
int main()
{
    int ch,n2,n3,i;
    start=start1=start2=NULL;
    do
    {
        printf("\n0.create list\n1.list of no divisible by 3.\n2.list of no not divisible by 3.\n3.display.\n4.exit\nenter choice:");
 scanf("%d",&ch);
 switch(ch)
 {
     case 0:printf("how many node you want to create:");
     scanf("%d",&n2);
     for(i=0;i<n2;i++)
     {
         printf("\nenter element:");
  scanf("%d",&n3);
  create(n3);
     }
     break;
     case 1:displaydiv3();
     break;
     case 2:displaynotdiv3();
     break;
     case 3:display();
     break;
     case 4: break;
     default:
      printf("invalid choice\n");
 }
    }while(ch!=4);

return 0;
}

void create(int m)
{
    struct node *p,*q;
    p=(struct node*)malloc(sizeof(struct node));    //complete list.
    p->data=m;
    p->next=NULL;
    if(start==NULL){ start=p;}  
    else {  q=start; while(q->next!=NULL){ q=q->next; }q->next=p; }
    if(m%3==0)
    {
        struct node *p1,*q1;
 p1=(struct node*)malloc(sizeof(struct node));                  // list with no divisible by 3.
 p1->data=m;
 p1->next=NULL;
 if(start1==NULL){ start1=p1;}  
 else {  q1=start1; while(q1->next!=NULL){ q1=q1->next; }q1->next=p1;} 
    }
    else
    {
        struct node *p2,*q2;
 p2=(struct node*)malloc(sizeof(struct node));   // list with other no which are not divisible by 3. 
 p2->data=m;
 p2->next=NULL;
 if(start2==NULL){ start2=p2;}  
 else {  q2=start2; while(q2->next!=NULL){ q2=q2->next; }q2->next=p2;} 
    }

}
void display()
{
    struct node *p;
    p=start;
    if(p==NULL){ printf("\nthere is no element in list\n");   return;}
    while(p!=NULL)
    {
        printf("%d\t",p->data);
 p=p->next;
    }
}

void displaynotdiv3()
{
    struct node *p;
    p=start2;
    if(p==NULL){ printf("\nthere is no element in list\n");   return;}
    while(p!=NULL)
    {
        printf("%d\t",p->data);
 p=p->next;
    }
}

void displaydiv3()
{
    struct node *p;
    p=start1;
    if(p==NULL){ printf("\nthere is no element in list\n");   return;}
    while(p!=NULL)
    {
        printf("%d\t",p->data);
 p=p->next;
    }
}

c assignment 5

↓↑ Program to show operations on structure like find offset,access using arrow operator. 

#include<stdio.h>
#include<stddef.h>
struct student
{
 int rollno;
 char name[10];
 int marks;
}s1;

int main()
{
        printf("Enter rollno name marks of student:");   // i/p  o/p operation
 scanf("%d%s%d",&s1.rollno,s1.name,&s1.marks);
 
 printf("rollno=%d\nname=%s\nmarks=%d\n\n",s1.rollno,s1.name,s1.marks);

 struct student s2={3,"nikhil",70};                                       //initialization of variable.............
 printf("rollno=%d\nname=%s\nmarks=%d\n\n",s2.rollno,s2.name,s2.marks);
 
 struct student *p=&s2;
        printf("rollno=%d\nname=%s\nmarks=%d\n\n",p->rollno,p->name,p->marks);

 printf("size of s1=%ld\nsize of *p=%ld\n",sizeof(s1),sizeof(p));
        printf("rollno offset=%ld name offset=%ld \nmarks offset=%ld\n",offsetof(struct student,rollno),offsetof(struct student,name),offsetof(struct student,marks));
 
 typedef struct student sinfo;                                            // alias for structure
 sinfo s3={3,"gaurav",60};                  
 printf("rollno=%d\nname=%s\nmarks=%d\n\n",s2.rollno,s2.name,s2.marks);
 
 typedef struct student *pstruct;                                        // alias for structure pointer
 pstruct p2=&s3;
 printf("rollno=%d\nname=%s\nmarks=%d\n\n",p2->rollno,p2->name,p2->marks);
return 0;
}



↓↑ Program to demonstrate efficient way of structure 
   declaration(different behaviour on 64 bit machine there word size is 64bit). 

#include<stdio.h>
#include<stddef.h>

struct A 
{
    int x;
    char c1;
    double d;
    float f;
    char c2;
};

struct B {
    char c1;
    char c2;
    int x;
    float f;
    double d;
};


int main()
{
    struct A a;
    struct B b;
    printf("befor optimization size of struct A=%d\nafter optimization size of struct B=%d\n",sizeof(a),sizeof(b));
    printf("offset x=%d,c1=%d,d=%d,f=%d,c2=%d\n",offsetof(struct A,x),offsetof(struct A,c1),offsetof(struct A,d),offsetof(struct A,f),offsetof(struct A,c2));
    printf("After\n\n");
    printf("offset x=%d,c1=%d,d=%d,f=%d,c2=%d\n",offsetof(struct B,x),offsetof(struct B,c1),offsetof(struct B,d),offsetof(struct B,f),offsetof(struct B,c2));

return 0;
}
//op on 32 bit 
//size of struct A = 20 bytes
//size of struct B = 16 bytes(place small data type first for better memory utilisation)


↓↑ Create a Box structure with the members length,breadth,height.Pass the structure 
   variable to a function to calculate volume by value, by reference 

#include<stdio.h>
struct box
{
    int length;
    int breadth;
    int width;
};

int vol(struct box);
int revol(struct box *);

int main()
{
    struct box a={10,20,30};
    int x,y;
    x=vol(a);
    printf("volume using call by function:%d\n",x);
    y=revol(&a);
    printf("volume using call by reference:%d\n",y);

return 0;
}

int vol(struct box b1)
{
    return (b1.length*b1.breadth*b1.width);
}

int revol(struct box *b2)
{
    return (b2->length*b2->breadth*b2->width);
}


↓↑ create student structure and modify marks member as an array(array of 5 subjects),  
   create array of struct variables and do some input,output operations.
   (Marks of i th student in j th subject etc) 

#include<stdio.h>
#include<stddef.h>
struct stud
{
    int rollno;
    char name[20];
    double marks[5];
};
void display(struct stud *,int );
void insert(struct stud *);

int records=0;
int main()
{
    int ch,rol,i;
    struct stud s[5];
    do
    {
        printf("\nEnter choice 1.Insert 2.Show 3.Exit");
        scanf(" %d",&ch);
 switch(ch)
 {
  case 1:
   insert(&s[records]);
   break;
  case 2:
   printf("\nEnter Roll No of student");
   scanf("%d",&rol);
   for(i=0;i<records;i++)
   {
    if(s[i].rollno==rol)
    display(&s[i],i);
    else printf("\nNo such student");
   }
  case 3:
   break;
  default:
   printf("\nWrong Choice...");     
                        break;
        }
    }while(ch!=3);
return 0;
}
void insert(struct stud *ptr)
{ 
    if(records<5)
    {
        int i;
        printf("\nEnter Roll No");
        scanf("%d",&(ptr[records].rollno));
        printf("\nEnter Name \n");
        scanf(" %s",ptr[records].name);
        for(i=0;i<5;i++)
        {
            printf("\nEnter Marks of Subject %d\n",i+1);
            scanf(" %lf",&ptr[records].marks[i]);
        }
    records++;
    }
}
void display(struct stud *ptr,int i)
{
    int j;
    printf("\nName=%s",ptr[i].name);
    printf("\nRoll No=%d",ptr[i].rollno);
    printf("\nEnter which subjects marks do you want\n");
    scanf("%d",&j);
    printf("\nMarks of Subject %d are \t%lf",j,ptr[i].marks[j-1]);
}


↓↑ Create program that return structure variable and 1 better approach 

#include<stdio.h>
struct stud
{
    int a,b;
};
struct stud return1(struct stud);
void return2(struct stud *);

int main()
{
    struct stud s1={12,13};
    struct stud s2,s4;
    s2=return1(s1);
    printf("val of a=%d,b=%d\n",s2.a,s2.b);            //a=22,b=23

    return2(&s1);

    printf("better approch no need to return structure\na=%d\tb=%d\n",s1.a,s1.b);// a=33,b=34
return 0;
}

struct stud return1(struct stud a1)
{
    a1.a=22;
    a1.b=23;
return a1;
}

void return2(struct stud *s3)
{
    s3->a=33;
    s3->b=34;
}


↓↑ Anonymous structure variable with and without typedef. 

#include <stdio.h>

struct
{
    int a;
    char name[10];
}b1;

struct
{
    int rollno;
}typedef s1;

int main()
{ 
    s1 a1;
    a1.rollno=34;
    b1.a=10;
    printf("%d %d\n",b1.a,a1.rollno);   
return 0;
}



↓↑ Nested Structure Example. 

#include<stdio.h>
struct A
{
    int add;
    double d;
    struct B{
        int age;
 char name[10];
    }b1;
}a1;

int main()
{
    a1.add=10;
    a1.b1.age=20;
    printf("inner structure age=%d,outer structure add=%d\n",a1.b1.age,a1.add);
return 0;
}


↓↑ Structure Bitfield Example. 

#include<stdio.h>
struct bit
{
    unsigned int a:4;
    //float b:6;
    unsigned int b:5;
}b1;

int main()
{
    b1.a=31;
    b1.b=31;
    //b1.b=2.23;
    printf("size of b1=%ld\ta=%d\tb=%d\n",sizeof(b1),b1.a,b1.b);
return 0;
}


↓↑ Program to convert ip address to unsigned int. 

#include<stdio.h>
#include<math.h>
union u
{

char ch[4];

 unsigned int i;
};
int main()
{
 int a,b,c,d,num;
 union u u1;
 printf("\nEnter Ip Address(enter each part without . or : )...");
 scanf("%d%d%d%d",&a,&b,&c,&d);
 u1.ch[0]=d;
 u1.ch[1]=c;
 u1.ch[2]=b;
 u1.ch[3]=a;
 printf("\n32Bit Integer is %u",u1.i);
 return 0;
}
//(first octet * 256³) + (second octet * 256²) + (third octet * 256) + (fourth octet)


↓↑ Union example. 

#include<stdio.h>
#include<stddef.h>
union A
{
 int x;
 int y;
 char ch;
};

union A a1;


int main()
{
 a1.x=0x10;
 a1.y=0x1121;
 a1.ch='A';
 printf("x=%d y=%d ch=%d\n",a1.x,a1.y,a1.ch);
 
 printf("size of union A=%ld\noffset of x=%ld\noffsetof y=%ld\noffset of ch=%ld\n",sizeof(a1),offsetof(union A,x),offsetof(union A,y),offsetof(union A,ch));

return 0;
}


↓↑ Union Inside Structure.

#include <stdio.h>
/*struct student
{
 int rollno;
 char name;
 union p{
  int age1;
  int age2;
  }p1;
}s1;*/
union student
{
 int rollno;
 char name;
 struct p{
  int age1;
  int age2;
  }p1;
}s1;
int main()
{
       /* s1.p1.age1=20;
 s1.p1.age2=22;
        s1.rollno=34;
        s1.name='A';*/

 s1.rollno=1023;
        s1.name='b';
 s1.p1.age1=20;
 s1.p1.age2=22; 
 //printf("rollno=%d name=%c\n",s1.rollno,s1.name);     
 printf("age1=%d age2=%d rollno=%d name=%c\n",s1.p1.age1,s1.p1.age2,s1.rollno,s1.name);
return 0;
}

c assignment 4

↓↑ Program to count Number of 1's in binary number. 

#include<stdio.h>
void bin(int);
static int c=0;
int main()
{
    int n;
    printf("enter decimal number :");
    scanf("%d",&n);
    printf("\nbinary number is:");
    bin(n);
    printf("\nno of one=%d\n",c);

return 0;
}
void bin(int n)
{
    int r;
    if(n!=0)
    {
     r=n%2;
 if(r)c++;
        n=n/2;
 bin(n);
 printf("%d",r);
    }
    else 
        printf(" ");
}


↓↑ Program to Find evaluation order of function parameters. 

#include<stdio.h>
void test(int,int,int);
int main()
{
    int i=6; 
    test(i++,i++,i++);   // Although behaviour undefined but most compilers follow right-to-left evaluation order.
    printf("\nAfter post:\n");
    test(++i,++i,++i);   
return 0;
}

void test(int a,int b,int c)
{
    printf("value:a=%d\tb=%d\tc=%d\n",a,b,c);
    printf("address:a=%u\tb=%u\tc=%u\n",&a,&b,&c);
}





↓↑ Program to calculate factorial of number correctly till 1...20. 

#include<stdio.h>
long long int fact(int n);
int main()
{
    int n;
    long long int factN;
    printf("enter number:");
    scanf("%d",&n);
    factN=fact(n);
    printf("value of factorial %d is:%lld\n",n,factN);
return 0;
}

long long int fact(int n)
{
    if(n==0)
        return 1;
    else
        return n*fact(n-1);
}


↓↑ Program to calculate factorial of very large number(with math lib). 

#include <stdio.h>
#include <math.h>
#include <string.h>

void multd(char * s, size_t len, unsigned n)
{
    unsigned values[len];
    size_t i;
    memset(values, 0, sizeof(unsigned) * len);
    for(i = len; i--; )
    {
        unsigned x = values[i] + (s[i] - '0') * n;
        s[i] = '0' + x % 10;
        if(i) values[i - 1] += x / 10;
    }
}

void factd(char * s, size_t len, unsigned n)
{
    memset(s, '0', len - 1);
    s[len - 1] = '1';
    for(; n > 1; --n) multd(s, len, n);
}

int main(void)
{
    unsigned num = 5;
    size_t len = ceill(log10l(tgammal(num + 1)));
    char dstr[len + 1];
    dstr[len] = 0;
    factd(dstr, len, num);
    puts(dstr);
}


↓↑ Program to calculate factorial of very large number(with gmp lib). 

// There is no practical limit to the precision except the ones implied 
// by the available memory in the machine GMP runs on.
#include <stdio.h>
#include <gmp.h>

void fact(mpz_t r,int n){
    unsigned int i;
    mpz_t temp;
    mpz_init(temp);
    mpz_set_ui(r,1);
    for(i=1;i<=n;i++){
        mpz_set_ui(temp,i);
        mpz_mul(r,r,temp);
    }
    mpz_clear(temp);
}
int main(void) {
    mpz_t r;
    mpz_init(r);
//    fact(r,188315);
    fact(r,100); 
    gmp_printf("%Zd\n",r);
    mpz_clear(r);
return(0);
}
//https://gmplib.org/
//sudo apt-get install  libgmp3-dev or sudo yum install  libgmp3-dev
//gcc factlargernumber.c -lgmp


↓↑ Program to print fibonacci series upto given length. 

#include<stdio.h>
void fib(int,int,int);
int main()
{
    int f0=0,f1=1,len;
    printf("Enter fibonaci series length: ");
    scanf("%d",&len);  
    fib(f0,f1,len);
    printf("\n");
return 0;
}
void fib(int current,int old,int l)
{
    static int i=0;
    int new;
    if(i<l)
    {
        new=current+old;
        printf("%d ",new);
        old=current;
        current=new;
        i++;
        fib(current,old,l);
    }
    else
        return;  
}


↓↑ Program to demonstrate function pointer. 

#include<stdio.h>
int test(int,int,int (*fp)(int,int));
int (*fp)(int,int);
int sum(int,int);

int main()
{
    int a=3,b=4,sm;
    fp=sum;
    sm=test(a,b,sum);
    printf("sum=%d\n",sm);
return 0;
}

int sum(int a,int b)
{
    return (a+b);
}

int test(int a,int b,int (*fp)(int a,int b))
{
    return fp(a,b);
}


↓↑ Menu based Program using function pointer. 

#include<stdio.h>
int test(int,int,int (*fp)(int,int));
int sum(int,int);
int prod(int,int);
int div(int,int);
int sub(int,int);

int main()
{
    int a=4,b=2,choice,result,(*fp[4])(int,int);
    fp[0]=sum;
    fp[1]=sub;
    fp[2]=prod;
    fp[3]=div;
    printf("enter your choice.\n0.addition\n1.substraction\n2.multiplication\n3.division\n");
    scanf("%d",&choice);
    result=test(a,b,fp[choice]);
    printf("%d\n",result);
return 0;
}

int sum(int a,int b)
{
    printf("\nsum=");
    return (a+b);
}

int prod(int a,int b)
{
    printf("\nproduct=");
    return(a*b);
}

int sub(int a,int b)
{
    printf("\nsubstraction=");
    return (a-b);
}

int div(int a,int b)
{
    printf("\ndivision=");
    return(a/b);
}
int test(int a,int b,int (*fp)(int a,int b))
{
    return fp(a,b);
}


↓↑ Program to calculate GCD of two number using recursion. 

#include<stdio.h>
int gcd(int,int);
int main()
{
 int x,y,gcd1;
 printf("enter two no.");
 scanf("%d%d",&x,&y);
 gcd1=gcd(x,y);
 printf("gcd of two no is:%d\n",gcd1);
return 0;
}
int gcd(int x,int y)
{
 if(x==y)
  return x;
 else if(x>y)
  return gcd(x-y,y);
 else
  return gcd(x,y-x); 
}       
       


↓↑ Make file demonstration 

//copy all parts in different files and keep in same directory
// then simply type ( make ) on terminal

makefile ->

all.out:mainp.o sump.o squarep.o
 gcc main16.o sum16.o square16.o -o all.out
mainp.o:mainp.c
 gcc main16.c -c
sump.o:sump.c
 gcc sum16.c -c
squarep.o:squarep.c 
 gcc square16.c -c

mainp.c ->

#include<stdio.h>
#include<math.h>
int sum(int,int);
int square(int);
int main()
{
int a=3,b=8,sm,sqr;
sm=sum(a,b);
printf("sum=%d\n",sm);
sqr=square(a);
printf("sqr=%d\n",sqr);
return 0;
}

sump.c -> 

int sum(int x,int y)
{
return x+y;
}

squarep.c ->

int square(int x)
{
return x*x;
}


↓↑ Program to pass 1 D array as function argument. 

#include<stdio.h>
int sumall(int*,int);
int min(int*,int);
int max(int*,int);
int main()
{
    int a[7]={10,12,19,14,9,18,11},s,mn,mx;
    s=sumall(a,7);
    mn=min(a,7);
    mx=max(a,7);
    printf("\nsum of 1-D array element is=%d\n",s);
    printf("\nmin of 1-D array element is=%d\n",mn);
    printf("\nmax of 1-D array element is=%d\n",mx);
return 0;
}
int sumall(int*p,int n)
{
    int i,sm=0;
    for(i=0;i<n;i++)
    {
        sm+=*(p+i);
        printf("%d ",*(p+i));
    }
return sm;
}
int min(int *p,int n)
{
    int a=12323,i;
    for(i=0;i<n;i++)
    {
        if(*(p+i)<a)
        {
            a=*(p+i);
        }
    }
return a;
}

int max(int *p,int n)
{
    int a=-32452,i;
    for(i=0;i<n;i++)
    {
        if(*(p+i)>a)
        {
            a=*(p+i);
        }
    }   
return a;
}


↓↑ Program to pass 2 D array as function argument. 

#include<stdio.h>
int summatrix(int nr,int nc,int (*p)[7]);
int main()
{
    int a[2][7]={10,12,13,23,34,32,33,26,13,19,14,9,18,11},s;
    s=sumall(2,7,a);
    printf("\nsum of 2-D array element is=%d\n",s);
return 0;
}
int sumall(int nr,int nc,int (*p)[7])
{
    int i,j,sm=0;
    for(i=0;i<nr;i++)
    {
         printf("\n");
        for(j=0;j<nc;j++)
        {
            sm+=*(*(p+i)+j);
//            printf("%d ",*(*(p+i)+j));
        }
    }
return sm;
}



↓↑ Program to return array from function. 

#include<stdio.h>
int* fun(int[],int);
int main()
{
int c[5]={4,7,8,9,6},i,*p;
p=fun(c,5);
for(i=0;i<5;i++)
printf("%d\t",*(p+i));
printf("\n");
return 0;
}

int* fun(int x[],int n)
{
 int i;
 for(i=0;i<n;i++)
 {
  x[i]=x[i]+1;
 // printf("%d\t",x[i]);
 }
 printf("\n");
return x;

}




↓↑ Program to calculate sum of N natural number usung recursion. 

#include<stdio.h>
int sum(int);
int main()
{
int n,n1;
printf("enter no.");
scanf("%d",&n);
n1=sum(n);
printf("sum of %d numbers is:%d\n1",n,n1);
return 0;
}


int sum(int n)
{
if(n==0)
return 0;
else
return n+sum(n-1);
}


↓↑ Program to demonstrate typedef for function pointer. 

#include<stdio.h>
typedef int (*pftype)(); 
int sum(int,int);
int main()
{
    int a=4,b=7;
    pftype pf1;
    pf1=sum; 
    pf1(a,b);
return 0;
}

int sum(int x,int y)
{
    printf("sum=%d\n",x+y);
}

ASCII Codes Table

ASCII Hex Symbol 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 A B C D E F NUL SOH STX ETX EOT ENQ ACK BEL BS TAB LF VT FF CR SO SI	ASCII Hex Symbol 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US	ASCII Hex Symbol 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F (space) ! " # $ % & ' ( ) * + , - . /	ASCII Hex Symbol 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 0 1 2 3 4 5 6 7 8 9 : ; < = > ?
ASCII Hex Symbol 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F @ A B C D E F G H I J K L M N O	ASCII Hex Symbol 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F P Q R S T U V W X Y Z [ \ ] ^ _	ASCII Hex Symbol 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F ` a b c d e f g h i j k l m n o	ASCII Hex Symbol 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F p q r s t u v w x y z { | } ~ 

c assignment 3

↓↑ Program to find second maximum element in array.

#include<stdio.h>
int main()
{
//    int arr[]={15,50,45,30,50};// here max1=50 max2=50
    int arr[]={15,50,45,30,5}; //here max1=50 max2=45
    int i,max1,max2,len=sizeof(arr)/sizeof(arr[0]);
    if(arr[0]>arr[1]){
        max1=arr[0];
        max2=arr[1];
    }else{
        max1=arr[1];
        max2=arr[0];
    }
    for(i=2;i<len;i++)
    {
        if(max1<arr[i]){
            max2=max1;
            max1=arr[i];
        }else if(max2<arr[i] /*&& max1>arr[i]*/){
                max2=arr[i];
        }
        else{}
    }
    printf("max1=%d max2=%d \n",max1,max2);
return 0;
}


↓↑ Program for number system(Binary,octal,hexadecimal,decimal)conversion.

#include<stdio.h>
int main()
{
    int a[32],b[32],i,j,choice,n,count=0;
    char ch=' ';
do{
    printf("************************************\n");
    printf("1.Decimal to binary.\n");
    printf("2.decimal to octal.\n");
    printf("3.decimal to hexadecimal.\n");
    printf("4.binary to decimal.\n");
    printf("5.binary to octal\n");
    printf("6.binary to hexadecimal.\n");
    printf("7.EXIT\n****************************\n");
 
    printf("Enter your choice:");
    scanf("%d",&choice);
    long int d,rem,n1;
    if(choice<1 && choice>7)
    {
     choice=0;
    }

    switch(choice)
    {
    case 1:
    printf("\nEnter decimal No. :");
    scanf("%d",&n);
    i=0;
    while(n)
    {
        a[i]=n%2;
        n=n/2;
        i++;
        count++;     
        }
        for(j=0,i=count-1;j<count,i>=0;j++,i--)
        {
            b[j]=a[i];
        } 
        printf("Binary no is:");
        for(i=0;i<count;i++){
        printf("%d",b[i]);}
        printf("\n");
    break;
    case 2:
    printf("\nEnter decimal No. :");
    scanf("%d",&n);
    i=0;
    while(n)
    {
        a[i]=n%8;
        n=n/8;
        i++;
        count++;     
    }
    for(j=0,i=count-1;j<count,i>=0;j++,i--)
    {
        b[j]=a[i];
    } 
    printf("octal no is:");
    for(i=0;i<count;i++){
        printf("%d",b[i]);
    }
    printf("\n");
    break;
    case 3:
    printf("\nEnter decimal No. :");
    scanf("%d",&n);
    i=0;
    while(n)
    {
        a[i]=n%16;
        n=n/16;
        i++;
        count++;     
    }
    for(j=0,i=count-1;j<count,i>=0;j++,i--)
    {
        b[j]=a[i];
    } 
    printf("hexadcimal no is:");
    for(i=0;i<count;i++)
    {
        if(b[i]==10||b[i]==11||b[i]==12||b[i]==13||b[i]==14||b[i]==15)
            printf("%c",b[i]+55);
        else 
            printf("%d",b[i]);
    }
     printf("\n");
   
    break;
    case 4:
    j=1;d=0;
    printf("Enter any binary number: ");      
    scanf("%ld",&n1);
    while(n1!=0){
        rem=n1%10;
        d=d+rem*j;
        j=j*2;
        n1=n1/10;
    }
    printf("Equivalent decimal value: %ld\n",d);
    break;
    case 5:
    j=1;d=0;
    printf("Enter any binary number: ");      
    scanf("%ld",&n1);
    while(n1!=0){
        rem=n1%10;
        d=d+rem*j;
        j=j*2;
        n1=n1/10;
    }
    printf("Equivalent octal value: %lo\n",d);
    break;
    case 6:
    j=1;d=0;
    printf("Enter any binary number: ");      
    scanf("%ld",&n1);
    while(n1!=0){
        rem=n1%10;
        d=d+rem*j;
        j=j*2;
        n1=n1/10;
    }
        printf("Equivalent hexadecimal value: %lx\n",d);
    break;
    case 7:
  
    break;
    default:
            printf("Wrong choice !!!  enter choice any of(1 to 7)");
    }
    fflush(stdin);
    printf("want to  continue enter y/n :");
    scanf(" %c",&ch);
}while(ch=='y'||ch=='Y');    
return 0;
}


↓↑ Program to implement cramer's rule to compute two unknown.

#include<stdio.h>
float det(float[2][2],int);
int main()
{

    int n=2,a1,b1,c1,a2,b2,c2,a3,b3,c3;
    printf("Enter the coefficient a1,b1,c1 (a1x+b1y=c1)of first equation: \n");
    scanf("%d%d%d",&a1,&b1,&c1);
    printf("Enter the coefficient a2,b2,c2 (a2x+b2y=c2)of second equation: \n");
    scanf("%d%d%d",&a2,&b2,&c2);
    float m[2][2]={a1,b1,a2,b2},x1[2][2]={c1,b1,c2,b2},y1[2][2]={a1,c1,a2,c2},x,y;
    x=(det(x1,n))/(det(m,n));
    y=(det(y1,n))/(det(m,n));
    printf("x=%f\ty=%f\n",x,y);
return 0;
}

float det(float matrix[2][2],int n)
{
    int i, j, k;
    float det,ratio;
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            if(j>i){
                ratio = matrix[j][i]/matrix[i][i];
                for(k = 0; k < n; k++){
                    matrix[j][k] -=ratio * matrix[i][k];
                }
            }    
        }
    }
    det = 1;                                            //storage for determinant
    for(i = 0; i < n; i++)
        det *= matrix[i][i];
    //printf("The determinant of matrix is: %.2f\n\n", det);
return det;
}
/*output:
 * 4x-3y=11
 * 6x+5y=7
 Enter the coefficient a1,b1,c1 (a1x+b1y=c1)of first equation: 
 4
 -3
 11
 Enter the coefficient a2,b2,c2 (a2x+b2y=c2)of second equation: 
 6
 5
 7
 x=2.000000 y=-1.000000
 */


↓↑ Program to implement cramer's rule to compute three unknown.

#include<stdio.h>
float det(float[3][3],int);
int main()
{

    int n=3,a1,b1,c1,d1,a2,b2,c2,d2,a3,b3,c3,d3;
    printf("Enter the coefficient a1,b1,c1,d1 (a1x+b1y+c1z=d1) of first equation: \n");
    scanf("%d%d%d%d",&a1,&b1,&c1,&d1);
    printf("Enter the coefficient a2,b2,c2,d2 (a2x+b2y+c2z=d2)of second equation: \n");
    scanf("%d%d%d%d",&a2,&b2,&c2,&d2);
    printf("Enter the coefficient a2,b2,c2,d2 (a3x+b3y+c3z=d3)of second equation: \n");
    scanf("%d%d%d%d",&a3,&b3,&c3,&d3);
    float m[3][3]={a1,b1,c1,a2,b2,c2,a3,b3,c3},x1[3][3]={d1,b1,c1,d2,b2,c2,d3,b3,c3},y1[3][3]={a1,d1,c1,a2,d2,c2,a3,d3,c3},z1[3][3]={a1,b1,d1,a2,b2,d2,a3,b3,d3},x,y,z;
     x=(det(x1,n))/(det(m,n));
     y=(det(y1,n))/(det(m,n));
     z=(det(z1,n))/(det(m,n));
     printf("x=%.2f\ty=%.2f\tz=%.2f\n",x,y,z);
return 0;
}

float det(float matrix[3][3],int n)
{
    int i, j, k;
    float det,ratio;
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            if(j>i){
                ratio = matrix[j][i]/matrix[i][i];
                for(k = 0; k < n; k++){
                    matrix[j][k] -=ratio * matrix[i][k];
                }
            }
        }
    }
    det = 1;
    for(i = 0; i < n; i++)
        det *= matrix[i][i];
return det;
}
/*Output:
 * x+2y+3z=-5
 * 3x+y-3z=4
 * -3x+4y+7z=-7
 Enter the coefficient a1,b1,c1,d1 (a1x+b1y+c1z=d1) of first equation: 
 1
 2
 3
 -5
 Enter the coefficient a2,b2,c2,d2 (a2x+b2y+c2z=d2)of second equation: 
 3
 1
 -3
 4
 Enter the coefficient a2,b2,c2,d2 (a3x+b3y+c3z=d3)of second equation: 
 -3
 4
 7
 -7
 x=-1.00    y=1.00  z=-2.00
 */


↓↑ Program to calculate determent of matrix connverting to upper triangular matrix.

#include<stdio.h>
int main()
{
    float  matrix[10][10], ratio, det;
    int i, j, k, n;
    clrscr();
    printf("Enter order of matrix: ");
    scanf("%d", &n);
    printf("Enter the matrix: \n");
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            scanf("%f", &matrix[i][j]);
        }
    }
                                                       //  Conversion of matrix to upper triangular
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            if(j>i){
                ratio = matrix[j][i]/matrix[i][i];
                for(k = 0; k < n; k++){
                    matrix[j][k] -=ratio * matrix[i][k];
                }
            }
        }
    }
    det = 1;                                            //storage for determinant
    for(i = 0; i < n; i++)
        det *= matrix[i][i];
    printf("The determinant of matrix is: %.2f\n\n", det);
return 0;
}


↓↑ Program to generate Identity matrix.

#include<stdio.h>
int main()
{
    int a[5][5],i,j,r,c;
    printf("enter rows and columns of matrix:");
    scanf("%d %d",&r,&c);
    if(r==c)
    {
        printf("\nenter element of %dX%d matrix:",r,c);
        for(i=0;i<r;i++)
        {
            for(j=0;j<c;j++)
            {
                scanf("%d",&a[i][j]);
            }
        }
    printf("\nentered matrix is ");
    for(i=0;i<r;i++)
    {
        printf("\n");
        for(j=0;j<c;j++)
        {
            printf("%d\t",a[i][j]);
        } 
    } 
    printf("\nidentity matrix corresponding to given matrix is:\n");
    for(i=0;i<r;i++)
    {
        printf("\n");
        for(j=0;j<c;j++)
        {
            if(i==j)
            {
                a[i][j]=1;
                printf("%d\t",a[i][j]);
            }
            else
           {
               a[i][j]=0;
               printf("%d\t",a[i][j]);
           }
        }
    } 
        printf("\n"); 
    }
    else
    {
        printf("to generate identity matrix rows and columns should be equal\n");
    }
return 0;
}


↓↑ Program to find minimum and maximum element in an array.

#include<stdio.h>
int main()
{
    int i,a[7],max=0,min=32432;
    printf("enter elements of array:");
    for(i=0;i<7;i++)
    {
        scanf("%d",&a[i]);
    }
    for(i=0;i<7;i++)
    {
        if(a[i]>max)
        {
            max=a[i];
        }
        if(a[i]<min)
        {
            min=a[i];
        }
    }
    printf("\nmaximum value is:%d\nminimum value is:%d\n",max,min);
return 0;
}


↓↑ Program to Implement matrix multiplication.

#include<stdio.h>
int main()
{
    int a[3][3],b[3][3],c[3][3],i,j,k,sum=0,m,n,o,p;
    printf("\nEnter the row and column of first matrix:");
    scanf("%d %d",&m,&n);
    printf("\nEnter the row and column of second matrix:");
    scanf("%d %d",&o,&p);
    if(n!=o)
    {
        printf("Matrix mutiplication is not possible");
        printf("\nColumn of first matrix must be same as row of second matrix");
    }
    else
    {
        printf("\nEnter the First matrix->");
        for(i=0;i<m;i++)
            for(j=0;j<n;j++)
                scanf("%d",&a[i][j]);      
        printf("\nEnter the Second matrix->");
        for(i=0;i<o;i++)
            for(j=0;j<p;j++)
                scanf("%d",&b[i][j]);
     
        printf("\nThe First matrix is\n");
        for(i=0;i<m;i++)
        {
            printf("\n");
            for(j=0;j<n;j++)
            {
                printf("%d\t",a[i][j]);
            }
        }         
        printf("\nThe Second matrix is\n");
        for(i=0;i<o;i++)
        {
            printf("\n");
            for(j=0;j<p;j++)
            {
                printf("%d\t",b[i][j]);
             }
        }
        for(i=0;i<m;i++)
            for(j=0;j<p;j++)
                c[i][j]=0;
        for(i=0;i<m;i++)
        {                                  //row of first matrix
            for(j=0;j<p;j++)
            {                                 //column of second matrix
                sum=0;
                for(k=0;k<n;k++)
                sum=sum+a[i][k]*b[k][j];
                c[i][j]=sum;
            }
        }
    }
    printf("\nThe multiplication of two matrix is\n");
    for(i=0;i<m;i++)
    {
        printf("\n");
        for(j=0;j<p;j++)
        {
            printf("%d\t",c[i][j]);
        }
    }
printf("\n");
return 0;
}


↓↑ Program to generate null matrix.

#include<stdio.h>
int main()
{
    int a[5][5],b[5][5],i,j,r,c;
    printf("enter rows and columns of matrix:");
    scanf("%d%d",&r,&c);
    printf("\nEnter the element of a matrix");
    for(i=0;i<r;i++)
    {
        for(j=0;j<c;j++)
        {
            scanf("%d",&a[i][j]);
         }
    }
    printf("\nEntered matrix is:\n");
    for(i=0;i<r;i++)
    { 
        for(j=0;j<c;j++)
        {
            printf("%d\t",a[i][j]);
        }
        printf("\n");
    }
    printf("\nNull matrix corresponding to given is:");
    for(i=0;i<r;i++)
    {
        printf("\n");
        for(j=0;j<c;j++)
        {
            b[i][j]=a[i][j]-a[i][j];
        }
    }
    for(i=0;i<r;i++)
    {
        for(j=0;j<c;j++)
        {
            printf("%d\t",b[i][j]);
        }  
        printf("\n");
    }
    printf("\n");
return 0;
}


↓↑ Program for pointer arithmetic.

#include<stdio.h>
int main()
{
    int x=3,*p,*p1,*p2;
    printf("intiger pointer\n");
    p=&x;
    printf("p=%u\n",p);
    p1=p+5;
    printf("p1=%u\n",p1);
    p2=p-5;
    printf("p2=%u\n",p2);
    printf("\np1++=%u \np2--=%u\np1-p2=%u\n",p1++,p2--,p1-p2);
    printf("\nfloat pointer\n");
    float y=3.2,*q,*q1,*q2;
    q=&y;
    printf("q=%u\n",q);
    q1=q+5;
    printf("q1=%u\n",q1);
    q2=q-5;
    printf("q2=%u\n",q2);
    printf("\nq1++=%u \nq2--=%u\nq1-q2=%u\n",q1++,q2--,q1-q2);
    printf("\ncharacter pointer\n");
    char r='3',*c,*c1,*c2;
    c=&r;
    printf("c=%u\n",c);
    c1=c+5;
    printf("c1=%u\n",c1);
    c2=c-5;
    printf("c2=%u\n",c2);
    printf("c1++=%u \nc2--=%u\nc1-c2=%u\n",c1++,c2--,c1-c2);
return 0;
}
/* //output 
ntiger pointer
p=106569296
p1=106569316
p2=106569276
p1++=106569316 
p2--=106569276
p1-p2=10
float pointer
q=106569300
q1=106569320
q2=106569280
q1++=106569320 
q2--=106569280
q1-q2=10
character pointer
c=106569295
c1=106569300
c2=106569290
c1++=106569300 
c2--=106569290
c1-c2=10
*/


↓↑ Program to reverse element of array .

#include<stdio.h>
#include<math.h>
int main()
{
    int i,a[]={12,10,11,33,23,13},len=sizeof(a)/sizeof(a[0]),temp;
    double alen =ceil((double)len/2);
        printf("\nArray before reverse: \n");
  
    for(i=0;i<len;i++)
    {
        printf("%d ",a[i]);
    }
    for(i=0;i<(int)alen;i++)
    {
        temp       = a[i];
        a[i]       = a[len-i-1];
        a[len-i-1] =temp;
    }
    printf("\nArray after reverse: ");
    for(i=0;i<len;i++)
    {
        printf("%d ",a[i]);
    }
    printf("\n");
return 0;
}
// compile with math library $gcc test.c -lm


↓↑ Program to print sum and average of array elements.

#include<stdio.h>
int main()
{
    int sum=0,avg,i,a[7];
    printf("enter elements of array:");
    for(i=0;i<7;i++)
    {
        scanf("%d",&a[i]);
    }
    printf("\nthe array is:"); 
    for(i=0;i<7;i++)
    {
        printf("%d ",a[i]);
    }
    printf("\nsum of array element is :");
    for(i=0;i<7;i++)
    {
        sum+=a[i];
    }
    printf("%d",sum);
    printf("\naverage of array element is:%d\n",sum/7);
return 0;
}


↓↑ Program to find trace of matrix.

#include<stdio.h>
int main()
{
    int a[5][5],i,j,sum=0,m,n;
    printf("\nEnter the row and column of matrix: ");
    scanf("%d %d",&m,&n);
    printf("\nEnter the elements of matrix: ");
    for(i=0;i<m;i++)
        for(j=0;j<n;j++)
            scanf("%d",&a[i][j]);
    printf("\nThe matrix is\n");
    for(i=0;i<m;i++)
    {
        printf("\n");
        for(j=0;j<m;j++)
        {
            printf("%d\t",a[i][j]);
        }
    }
    for(i=0;i<m;i++)
    {
        for(j=0;j<n;j++)
        {
            if(i==j)
                sum=sum+a[i][j];
        }
    }
    printf("\n\ntrace of a matrix is: %d",sum);
    printf("\n");
return 0;
}


↓↑ Program to find transpose of matrix.

#include<stdio.h>
int main()
{
    int a[6][6],b[6][6],i,j,k=0,m,n;
    printf("\nEnter the row and column of matrix:");
    scanf("%d %d",&m,&n);
    printf("\nEnter the First matrix->");
    for(i=0;i<m;i++)
        for(j=0;j<n;j++)
            scanf("%d",&a[i][j]);

    printf("\nThe matrix is\n");
    for(i=0;i<m;i++)
    {
        printf("\n");
        for(j=0;j<m;j++)
        {
             printf("%d\t",a[i][j]);
        }
    }
    for(i=0;i<m;i++)
       for(j=0;j<n;j++)
           b[i][j]=0;
    for(i=0;i<m;i++)
    {
        for(j=0;j<n;j++)
        {
            b[i][j]=a[j][i];
        }
    }
    printf("\n\nTraspose of a matrix is -> ");
    for(i=0;i<m;i++)
    {
        printf("\n");
        for(j=0;j<m;j++)
        {
            printf("%d\t",b[i][j]);
        }
    }
    printf("\n");
return 0;
}


↓↑ Program to check that a given matrix is identity matrix or not.

#include<stdio.h>
int main()
{
    int a[5][5],b[5][5],i,j,r,c,count=0,count1=0;
    printf("enter rows and columns of matrix:");
    scanf("%d%d",&r,&c);
    printf("\nEnter the element of a matrix");
    for(i=0;i<r;i++)
    {
        for(j=0;j<c;j++)
        {
            scanf("%d",&a[i][j]);
        }
    }
    printf("\nEntered matrix is:\n");
    for(i=0;i<r;i++)
    {
        for(j=0;j<c;j++)
        {
            printf("%d\t",a[i][j]);
        }
        printf("\n");
    }
    for(i=0;i<r;i++)
    {
        printf("\n");
        for(j=0;j<c;j++)
        {
            if(i==j && (a[i][j]==1))
            {
                ++count;
            }
            else if(i!=j && a[i][j]==0)
            {
                ++count1;
            }
        }
    }
    if(count==r && count1==(r*c-r))
    {
        printf("\nmatrix is identity");
    }
    else
        printf("\nmatrix is not identity");
    printf("\n");
return 0;
}


↓↑ Program to check null matrix.

#include<stdio.h>
int main()
{
    int a[5][5],b[5][5],i,j,r,c,count=0;
    printf("enter rows and columns of matrix:");
    scanf("%d%d",&r,&c);
    printf("\nEnter the element of a matrix");
    for(i=0;i<r;i++)
    {
        for(j=0;j<c;j++)
        {
            scanf("%d",&a[i][j]);
        }
    }
    printf("\nEntered matrix is:\n");
    for(i=0;i<r;i++)
    {
        for(j=0;j<c;j++)
        {
            printf("%d\t",a[i][j]);
        }
    printf("\n");
    }
    for(i=0;i<r;i++)
    {
        printf("\n");
        for(j=0;j<c;j++)
        {
            if(a[i][j]==0)
            {
                ++count;
            }
        }
    }
    if(count==r*c)
    {
        printf("\nmatrix is null");
    }
    else
        printf("\nmatrix is not null");
    printf("\n");
return 0;
}

c assignment 2

↓↑ Print range of various data types using constants declared in limits.h .

#include<stdio.h>
#include<limits.h>
int main()
{
    printf("range of char is %ld to %ld\n ",SCHAR_MIN,SCHAR_MAX);
    printf("range of int is %ld to %ld\n ",INT_MIN,INT_MAX);
    printf("range of longint is %ld to %ld\n ",LONG_MIN,LONG_MAX);
    printf("range of shortint is %d to %d\n ",SHRT_MIN,SHRT_MAX);

return 0;
}

↓↑ prgram to display int float using various format specifiers.

#include<stdio.h>
void showbit(int n);
int main()
{
    int i=65;
    float j=1.25f;
    printf("Intiger to decimal=%d ,octal=%o hexadecimal=%x ,scientific=%e character=%c and in binary= ",i,i,i,i,i,i);
    showbit(i);
    printf("\n");
    printf("float in scientific=%e\n",j); 
return 0;
}
void showbit(int n)
{
    int i,k,shift;
    for(i=15;i>=0;i-- )
    {
        shift=1<<i;
        k=n&shift;
        k==0?printf("0"):printf("1");
    }
}

↓↑ Programm to convert ip address to 32 bit unsigned integer.

#include<stdio.h>
#include<math.h>
int main()
{
    int a,b,c,d;
    unsigned int ip;
    printf("\nEnter IP Address...\n");
    scanf(" %d%d%d%d",&a,&b,&c,&d);
    if(a>255&&a<0 && b>255&&b<0 && c>255&&c<0 && d>255&&d<0)
    {
        printf("\nInvalid Ip...\n");
    }
    ip=a<<24|b<<16|c<<8|d;
    printf("\n\n%u",ip);
return 0;
}

↓↑ Program to converts a 32 bit unsigned integer to ip address.

#include<stdio.h>
#include<math.h>
int main()
{
    unsigned int num;
    int a,b,c,d;
    printf("\nEnter 32 bit unsigned number");
    scanf("%d",&num);
    a=num>>24; 
    b=(num<<8)>>24;
    c=(num<<16)>>24;
    d=(num<<24)>>24;
    printf("\n%d.%d.%d.%d",a,b,c,d);
return 0;
}

↓↑ Program to convert binary to decimal.

#include<stdio.h>
#include<math.h>
int main()
{
    int n,a[8],b[8],i,j;
    printf("enter binary no:");
    for(i=0;i<=7;i++)
    {
        scanf("%d",&a[i]);
    } 
    for(i=7,j=0;i>=0,j<=7;i--,j++)
    { 
        n+=a[j]*pow(2,i); 
    }
    printf("no in decimal is:%d\n",n);
return 0;
}

↓↑ Program to Evaluate various expressions with bitwise operatiors.

#include<stdio.h>
int main()
{
    int a=22,b=4;
    printf("result of bitwise or  is:%d\n",a|b);
    printf("result of bitwise and is:%d\n",a&b);
    printf("result of bitwise xor is:%d\n",a^b);
    printf("result of bitwise left shift is:%d\n",a<<b);
    printf("result of bitwise right shift is:%d\n",a>>b);
    printf("result of bitwise not is:%d\n",~a);
return 0;
}
output:
result of bitwise or  is:22
result of bitwise and is:4
result of bitwise xor is:18
result of bitwise left shift is:352
result of bitwise right shift is:1
result of bitwise not is:-23

↓↑ Program to Try various format specifiers in printf, scanf .

#include<stdio.h>
int main()
{
   int i=10;
   float j=20.56333;
   printf("%5d,%-5d,%05d,%8.2f,%-8.2f,%08.2f,%.2f,%.1f\n",i,i,i,j,j,j,j,j);
return 0;
}
output:
   10,10   ,00010,   20.56,20.56   ,00020.56,20.56,20.6

↓↑ expression using conditional operator to find biggest of 3 no.s.

biggest = a > b ? (a > c ? a : c) : (b > c ? b : c) ;

↓↑ Program In a given bit pattern(8,16 or 32 bit) write expressions for
a. set Kth bit
b. Reset Kth bit
c. Flip Kth bit
d. Query Kth bit1.

#include<stdio.h>
int main()
{
    int n,i=0,j=0,bin[32],b[32],count=0,choice,bit;
    printf("enter number:");
    scanf("%d",&n);
    while(n>=1)
    {
        bin[i]=n%2;
        n=n/2;
        i++;
        count++;
    }
    while(i>=0)
    {
        b[j]=bin[i-1];
        i--;
        j++;
    }
    printf("\nbinary no is:");
    for(i=0;i<count;i++ )
    {
        printf("%d ",b[i]);
    }
    printf("\nthere are : %d :bit in binary number\n",count);
    printf("**********************************************************\n");
    printf("Press 1,2,3,4,5 .............\n");
    printf("1.set Kth bit\n");
    printf("2.Reset Kth bit\n");
    printf("3.Flip Kth bit\n");
    printf("4.Query Kth bit\n");
    printf("5.Exit\n");
    printf("**********************************************************\n");
    printf("enter your choice:");
    scanf("%d",&choice);



    switch(choice)
    {
        case 1:
            printf("\nEnter which bit is to be set:");
            scanf("%d",&bit);
            if(b[count-bit]==1);
            else
                b[count-bit]=1;

            printf("\nBinary no after setting the bit:");
            for(i=0;i<count;i++ )
            {
                printf("%d ",b[i]);
            }
            printf("\n");
        break;
        case 2:
            printf("Enter which bit is to be Reset:\n");
            scanf("%d",&bit);
            (b[count-bit]==1)?(b[count-bit]=0):(b[count-bit]=0);

             printf("\nBinary no after setting the bit:");
             for(i=0;i<count;i++ )
             {
                 printf("%d ",b[i]);
             }
             printf("\n");

        break;
        case 3:
            printf("which bit is to be flip:\n");
            scanf("%d",&bit);
            if(b[count-bit]==0)
                b[count-bit]=1;
            else
                b[count-bit]=0;
            printf("\nBinary no after Flipping the bit:");
            for(i=0;i<count;i++ )
            {
                printf("%d ",b[i]);
            }
            printf("\n");
        break;
        case 4:
            printf("which bit is to be searched:\n");
            scanf("%d",&bit);
            printf(" %d bit is :%d\n",bit,b[count-bit]);
        break;
        case 5:


        break;
        default:
            printf("\ninvalid choice\n");
    }
return 0;
}

c assignment1

↓↑ Different ways to swap two number.

/*swap two no. using xor operator */
#include<stdio.h>
int main()
{
        int num1=12,num2=15;
        printf("No. Before swapping a=%d,b=%d\n",num1,num2);
/*      num1=num1^num2;
        num2=num1^num2;                       
        num1=num1^num2;
*/
//or in one line
        num1 ^= num2 ^= num1 ^= num2;
        printf("no after swapping a=%d,b=%d\n",num1,num2);
return 0;
}

/*swap two no. without using third variable */
#include<stdio.h>
int main()
{
        int num1=12,num2=15;
        printf("No. Before swapping a=%d,b=%d\n",num1,num2);
/*      num1=num1+num2;
        num2=num1-num2;
        num1=num1-num2;
*/
//or in one line
        num2 = num1 + num2 - (num1 = num2);
        printf("no after swapping a=%d,b=%d\n",num1,num2);
return 0;
}

/* swap two number using pointer */
#include<stdio.h>

void swap( int *num1, int *num2)
{
    int temp ;
    temp  = *num1 ;
    *num1 = *num2 ;
    *num2 = temp ;
}

int main( )
{
    int num1=12,num2=15;

    printf("beforee swap num1=%d num2=%d \n",num1,num2);
    swap(&num1,&num2) ;
    printf("after swap num1=%d num2=%d \n",num1,num2);

    return(0);
}

/* swap using 3 variable */
#include<stdio.h>
int main()
{
    int temp,num1=12,num2=15;
    printf("\nAfter Swapping, the numbers are:num1=%d num2=%d \n",num1,num2);
    temp = num1;
    num1 = num2;
    num2 = temp;
    printf("\nAfter Swapping, the numbers are:num1=%d num2=%d \n",num1,num2);
return 0;
}

/* swap using 2 Non-Zero variable*/
#include<stdio.h>
int main()
{
 int num1=12,num2=15;//both number should be non zero
       if(num1 != 0 && num2 != 0)
       {
          printf("\nBefore Swapping, the numbers are: num1=%d num2=%d \n",num1,num2);
          num1 = num1 * num2;
          num2 = num1/num2;
          num1 = num1/num2; 
//      or
/*        num2 = num1 * num2;
          num1 = num2/num1;
          num2 = num2/num1;   
*/        printf("\nAfter Swapping, the numbers are: num1=%d num2=%d \n",num1,num2);
       }
       else
       {
          printf("\n Both the numbers should be Non-Zero!");
       }

return 0;
}


↓↑ Program to reverse 4 digit number.

#include<stdio.h>
int main()
{
    int rev=0,rem,num;
    printf("\nenter four digit no.");
    scanf("%d",&amp;num);
    while(num&gt;0){
        rem=num%10;              //last digit is being extracted
        rev=rev*10+rem;          //reverse no. is being generated by extracted no.
        num=num/10;              //extracted no is being removed from original no.
    }
    printf("reverse of four digit no=%d\n",rev);
return 0;
}


↓↑ Program to check a year is Leap Year or not

#include<stdio.h>
int main()
{
    int year;
    printf("Enter year :");
    scanf("%d",&year);
    if(((year%4==0)&&(year%100!=0))||(year%400==0))      //condition for leap year
        printf("%d is a leap year\n",year);
    else
        printf("%d is not a leap year\n",year);
return 0;
}


↓↑ Program to draw shape
ABCDEFGFEDCBA
ABCDEF FEDCBA
ABCDE   EDCBA
ABCD     DCBA
ABC       CBA
AB         BA
A           A


#include<stdio.h>
int main()
{
    int row,i,j,k,space=1,limitl=71,limitr=65,count=0,temp;
    for(row=0;row<7;row++){  
         for(i=65;i<=limitl;i++){ //  first time PRINT ABCDEFG
             printf("%c",i); 
         }
         limitl--;

        if(row>0)
        {
             for(k=1;k<=space;k++) //FIRST TIME PRINT 0 SPACE 
             {
                 printf(" "); 
             }
         space=space+2;
        }

        temp=limitl;

        if(count==1)temp+=1;  // USED TO PRINT FEDCBA SECOND TIME AND ONE CHARACTER LESS ONWARDS
 
        for(j=temp;j>=limitr;j--){ // FIRST TIME PRINT FEDCBA
             printf("%c",j);
        }
        count=1;
        printf("\n");
    } 
return 0;
}


↓↑ Program to check greatest of three numbers.

#include<stdio.h>
int main()
{
    int num1,num2,num3;
    printf("Enter 3 Number :");
    scanf("%d\n%d\n%d",&num1,&num2,&num3);
    if(num1==num2 && num1==num3)                 //compare all number to each other number
        printf("all numbers are equal\n");
    else if(num1>num2 && num1>num3)              //compare first number to other numbers
        printf("num1=%d is greater\n",num1);
    else if(num2>num1 && num2>num3)              //compare second number to other numbers
        printf("num2=%d is greater\n",num2);
    else                                         //compare third number to other numbers
        printf("num3=%d is greater\n",num3);
return 0;
}


↓↑ Program to identify Quadrant of a point

#include<stdio.h>
int main()
{
    float x,y;
    printf("enter co-ordinate of a point :");
    scanf("%f\n%f",&x,&y);
    if(x==0 && y==0)                                           //condition if co-ordinate at origin
        printf("x=%f,y=%f is the origion\n",x,y);
    else if(x==0 && y>0 ||x==0 && y<0)                        //condition if co-ordinate at y axix
        printf("x=%f,y=%f point is on Y-axis\n",x,y);
    else if(x>0 && y==0 ||x<0 && y==0)                       //condition if co=ordinate at x axix
        printf("x=%f,y=%f point is on X-axis\n",x,y);
    else if(x>0 && y>0)                                     //condition if co-ordinate at first quardent
        printf("x=%f,y=%f are in 1st quadrant\n",x,y);
    else if(x<0 && y>0)                                     //condition if co-ordinate at second quardent
        printf("x=%f,y=%f are in 2nd quadrant\n",x,y);
    else if(x<0 && y<0)                                     //condition if co-ordinate at third quardent
        printf("x=%f,y=%f are in 3rd quadrant\n",x,y);
    else                                                    //condition if co-ordinate at fourth quardent
        printf("x=%f,y=%f are in 4th quadrant\n",x,y);
return 0;
}


↓↑ Recursive sum of digits in a no.
Eg:- sumdigits(5689) = 28, sumdigits(28) = 10, sumdigits(10) = 1.

#include<stdio.h>
int sum(int n);
int main()
{
    int i,n,s;
    printf("enter no.");
    scanf("%d",&n);
    s=sum(n);
    printf("recursive sum is =%d of number %d\n",s,n);
return 0;
}
int sum(int n)
{
    int sum1=0,rem,rem1,sum2=0;
    while(n>0)
    {
        rem=n%10;                //last digit is being extracted                              
        sum1+=rem;               //sum of all digit is being extracted
        n=n/10;                  // exponent is being extracted
    }  
    while(sum1>0)
    {
        rem1=sum1%10;            //last digit is being extracted from sum
        sum2+=rem1;              //sum of all digit is being extracted
        sum1=sum1/10;            //exponent is being extracted
    }
return sum2;
}


↓↑ Series generation 1 + x + x^2/2! + x^3/3!+...x^n/n!

#include<stdio.h>
int main()
{
    int x,n,i;
    printf("Enter the integer value of X and N:\n");
    scanf("%d\n%d",&x,&n);
    for(i=0;i<=n;i++)
    { 
        if(i!=0)printf("+");
            printf("%d^%d/%d!",x,i,i);
    }
    printf("\n\n");
return 0;
}


↓↑ Program to calculate GCD of two no.s do-while loop

#include<stdio.h>
int main()
{
    int x,y,i;
    printf("enter two no.");
    scanf("%d%d",&x,&y);
    i=y;
    do{
        if(x%i==0 && y%i==0)
        {
            printf("gcd of two no is :%d\n",i);
            break;
        }
        i--;
    }while(i>=1);
return 0;
}


↓↑ Program to calculate GCD of two no.s while loop

#include<stdio.h>
int main()
{
    int n1,n2,g;
    printf("\nEnter two no:");
    scanf("%d\n%d",&n1,&n2);
    g=gcd(n1,n2);
    printf("gcd of %d and %d is %d\n",n1,n2,g);
return 0;
}

int gcd(int a,int b)
{
    int c;
    while(1)
    {
        c=a%b;
        if(c==0)
            return b;
        a = b;
        b = c;
     }
}


↓↑ Program to calculate LCM of two no.s

#include<stdio.h>
int main()
{
    int n1,n2,l;
    printf("\nEnter two number:");
    scanf("%d\n%d",&n1,&n2);
    l=lcm(n1,n2);
    printf("lcm of %d and %d is =%d\n",n1,n2,l);
return 0;
}
int lcm(int a,int b)
{
    int n;
    for(n=1;;n++)
    {
        if(n%a == 0 && n%b == 0)          //condition for lcm
            return n;
    }
}


↓↑ Program to calculate ncr

#include<stdio.h>
int main()
{
    int n,r,ncr;
    printf("Enter any two numbers->");
    scanf("%d %d",&n,&r);
    if(n>=r)
    {
        ncr=fact(n)/(fact(r)*fact(n-r));
        printf("The NCR factor of %d and %d is: %d\n",n,r,ncr);
    }
    else
        printf("Value of N should be equal to or greater than R\n\n");
return 0;
}
int fact(int n)
{
    int i=1;
    while(n!=0)
    {
        i=i*n;
        n--;
    }
return i;
}


↓↑ Program to Print range of prime number till given number

#include<stdio.h>
int main()
{
    int limit,i,j,flag=0;
    printf("Enter Limit for prime numbers:");
    scanf("%d",&limit);
    printf("Prime no's are 2,");
    for(i=3;i<=limit;i++)
    {
        for(j=2;j<i;j++)
        {
            if(i%j==0)
                flag=1;
        }
        if(flag==0)
            printf("%d ",i);
        flag=0;
    }
    printf("\n");
return 0;
}


↓↑ Program to make triange shape1 with '*' .

#include<stdio.h>
int main()
{
    int line,i,j;
    printf("Enter the no. of lines: ");
    scanf("%d",&line);
    for(i=0;i<line;i++){
        for(j=0;j<line-i-1;j++)
            printf(" ");

        for(j=0;j<=i;j++)
            printf("* ");
        printf("\n");
    }
return 0;
}


↓↑ Program to make triange shape2 with '*' 

#include<stdio.h>
int main()
{
    int line,i,j;
    printf("Enter the no. of lines: ");
    scanf("%d",&line);
    for(i=0;i<line;i++){
         for(j=0;j<line-i-1;j++)
             printf(" ");

         for(j=0;j<=i;j++)
             printf("*");
         printf("\n");
    }
return 0;
}


↓↑ Program to make triange shape3 with '*' 

#include<stdio.h>
int main()
{
    int line,i,j;
    printf("enter no's of lines:");
    scanf("%d",&line);
    for(i=1;i<=line;i++)
    {
        for(j=1;j<=i;j++) 
        {
            printf("*");
        }
        printf("\n");
    }
return 0;
}


↓↑ Program to print Pascal triangle.

#include<stdio.h>
int fact(int n)
{
    int i=1;
    while(n!=0)
    {
        i=i*n;
        n--;
    }
return i;
}
int main()
{
    int line,i,j;
    printf("Enter the no. of lines: ");
    scanf("%d",&line);
    for(i=0;i<line;i++)
    {
        for(j=0;j<line-i-1;j++)
            printf(" ");

        for(j=0;j<=i;j++)
            printf("%d ",fact(i)/(fact(j)*fact(i-j)));
        printf("\n");
     }
return 0;
}


↓↑ Program to calculate Brute force multiplicative inverse

#include<stdio.h>
int modInverse(int a, int m) {
    a %= m;
    int x;
    for(x = 1; x < m; x++) {
        if((a*x) % m == 1) return x;
    }
}
int main()
{
    printf("\nmultiplicative inverse = %d\n",modInverse(42,2017));
return 0;
}


↓↑ Program for Extended Euclidean Algorithm to calculate multiplicative inverse

#include<stdio.h>
int mul_inv(int a, int b)
{
    int b0 = b, t, q;
    int x0 = 0, x1 = 1;
    if (b == 1) return 1;
    while (a > 1) {
        q = a / b;
        t = b, b = a % b, a = t;
        t = x0, x0 = x1 - q * x0, x1 = t;
    }
    if (x1 < 0) x1 += b0;
return x1;
}
int main(void) {
    printf("%d\n", mul_inv(42, 2017));
return 0;
}


↓↑ Electricity bill calculation as per following tariff
upto 100 Units : Rs.1,100-199 Units : Rs.2
200 – 399 units : Rs.3,400 units and above – Rs.4

#include<stdio.h>
int main()
{
    int unit,rs;
    printf("enter unit:");
    scanf("%d",&unit);
    if(unit<=99)                                 //total bill if unit <=99
    {
        rs=unit;
    }
    else if(unit>=100 && unit<=199)              //total bill if unit<= 199
    {
        rs=99+(unit-99)*2;
    }
    else if(unit>=200 && unit<=399)            //total bill if unit<=399
    {
        rs=299+(unit-199)*3;
    }
    else                                        //total bill if unit>=399
    {
        rs=899+(unit-399)*4;
    }

    printf("electricity bill of unit %d is %d\n",unit,rs);
return 0;
}


↓↑ Student grade using switch case as per following criteria
>= 70% - A grade, 60-69% - B grade 50 – 59%: C Grade, 30-49% - D grade
<30% - Fail

#include<stdio.h>
int grade(int p)
{
    if(p>=70)                                   // condition for A grade 
        return 1;
    else if(p>=60 && p<=69)                     // condition for B grade
        return 2;
    else if(p>=50 && p<=59)                      //condition for C grade
        return 3;
    else if(p>=30 && p<=49)                     //condition for D grade
        return 4;
    else                                          //condition for FAIL
        return 5;
}
int main()
{
    int percentage,i;
    printf("enter percentage:");
    scanf("%d",&percentage);
    i=grade(percentage);
    switch(i)
    { 
        case 1:
            printf("congratuation you passed with A-GRADE\n");
        break;
        case 2:
            printf("congratuation you  passed with B-GRADE\n");
        break;
        case 3:
            printf("congratuation you  passed with C-GRADE\n");
        break;
        case 4:
            printf("you passed with D-GRADE \n");
         break;
        default:
            printf("Sorry you are FAIL\n");                          
    }
return 0;
}