on Jul 07 2021 Comment

#include <stdio.h>

int main() {
    // Declare variables
    int n, i, flag = 0;

    // Prompt user for input
    printf("Enter a positive integer: ");
    scanf("%d", &n);

    // Iterate from 2 to n/2
    for (i = 2; i <= n/2; ++i) {
        // Check if n is divisible by i
        if (n % i == 0) {
            flag = 1;
            break;
        }
    }

    // Check and display the result
    if (n == 1) {
        printf("1 is neither a prime nor a composite number.");
    }
    else {
        if (flag == 0)
            printf("%d is a prime number.", n);
        else
            printf("%d is not a prime number.", n);
    }

    return 0;
}