deleteprime.c

//This code found the prime number in array and delete it;
#include<stdio.h>
#include<malloc.h>

int n; //taking n as global variables because it is being used by shrink fun as well and its value is changing in both mains and shrink function.


int isprime(int n)
{   int i,flag=0;
     for(i=2;i<=n/2;i++)
        {    if(n%i==0)
                { flag++;
                    break;
            }
        }
        if(flag==0 && n!=1)
        return 1;
        else
            return 0;
}

void shrink_arr(int *arr, int j)
{       printf("\n%d",j);
        if(j==n-1)
             arr[j]=4;//replacing last element with a non-prime number to stop the while loop in main function


     else
        { while(j<n-1)//keep shrinking till the last element
        /*'j' can maximum travel up to the 2nd last element so that j+1 become the last one*/
            {arr[j]=arr[j+1];
            j++;
            }
        }
        /*Since each time the shrink fun called, the array shrink by 1 element so n--;*/
        n--;
        return;
}

int main()
{
   int *arr,i,j;
     printf("Enter number of elements:. ");
    scanf("%d",&n);
    arr= calloc(n,sizeof(int));
    //Enter all (distinct) elements of array/
    for(i=0;i<n;i++)
    {    printf("Enter element %d: ",i+1);
        scanf("%d",&arr[i]);
    }

    printf("\n Here is the list:\n");
    for(i=0;i<n;i++)
      printf("%d ",arr[i]);

    for(i=0;i<n;i++)
    {    while(isprime(arr[i])==1)
            shrink_arr(arr,i);
    }
    printf("\n List without prime number:\n");
    if (n==0)
    printf("\nList is empty:");
    /*Since if 'n' = 0 then below for loop will not excecute hence no need for else statement*/
    for(i=0;i<n;i++)
      printf("%d ",arr[i]);





    free(arr);

    return 0;
}