Prime Number Program

primeno-3.c

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

int main()
{
    int n, i, half, isPrime = 1, square_root;
    
    printf("Enter Value of n... ");
    scanf("%d", &n);

    square_root = sqrt(n);
    if(n > 1)
    {
        for(i = 2 ; i <= square_root ; i++) // or for(i = 2 ; i * i <= n ; i++)
        {
            if(n % i == 0)
            {
                isPrime = 0;
                break;
            }
        }
    }
    else
        isPrime = 0;

    if(isPrime)
        printf("%d is a Prime Number.", n);
    else
        printf("%d is not a Prime Number.", n);
    return 0;
}