C Program to Check Whether a Number is Prime or Not - IProgramX

Q. Write a program to accept an integer and check if it is prime or not

Program

#include<stdio.h>
int main()
{
    int n, i, flag = 0;
    printf("Enter a positive integer: ");
    scanf("%d",&n);

    for(i=2; i<=n/2; ++i)
    {
        if(n%i==0)
        {
            flag=1;
            break;
        }
    }

    if (flag==0)
        printf("%d is a prime number.",n);
    else
        printf("%d is not a prime number.",n);
}

Output:

Enter a positive integer: 67
67 is a prime number.