c program to check prime number using for loop

1#include <stdio.h>
2int main() {
3    int n, i, flag = 0;
4    printf("Enter a positive integer: ");
5    scanf("%d", &n);
6
7    for (i = 2; i <= n / 2; ++i) {
8
9        // condition for non-prime
10        if (n % i == 0) {
11            flag = 1;
12            break;
13        }
14    }
15
16    if (n == 1) {
17        printf("1 is neither prime nor composite.");
18    }
19    else {
20        if (flag == 0)
21            printf("%d is a prime number.", n);
22        else
23            printf("%d is not a prime number.", n);
24    }
25
26    return 0;
27}
28

1#include <stdio.h>
2int main()
3{
4   int i, num, p = 0;
5   printf("Please enter a number: \n");
6   scanf("%d", &num);
7   for(i=1; i<=num; i++)
8   {
9      if(num%i==0)
10      {
11         p++;
12      }
13   }
14   if(p==2)
15   {
16      printf("Entered number is %d "\
17             "and it is a prime number.",num);
18   }
19   else
20   {
21      printf("Entered number is %d "\
22             "and it is not a prime number.",num);
23   }
24}
25