Write a Program to check whether a given number is prime or not and output the given number with suitable message

#include <stdio.h>

#include <stdlib.h>

void main()

{

    int num, j, flag;

    printf("Enter a number \n");

    scanf("%d", &num);

    if (num <= 1)

    {

        printf("%d is not a prime numbers \n", num);

        exit(1);

    }

    flag = 0;

    for (j = 2; j <= num / 2; j++)

    {

        if ((num % j) == 0)

        {

            flag = 1;

            break;

        }

    }

    if (flag == 0)

        printf("%d is a prime number \n", num);

     else

        printf("%d is not a prime number \n", num);

}

/*

INPUT :

Enter a number

257

OUTPUT :

257 is a prime number

*/