1#include <stdio.h>
2
3void checkPrimeNumber();
4
5int main()
6{
7 checkPrimeNumber(); // argument is not passed
8 return 0;
9}
10
11// return type is void meaning doesn't return any value
12void checkPrimeNumber()
13{
14 int n, i, flag = 0;
15
16 printf("Enter a positive integer: ");
17 scanf("%d",&n);
18
19 for(i=2; i <= n/2; ++i)
20 {
21 if(n%i == 0)
22 {
23 flag = 1;
24 }
25 }
26 if (flag == 1)
27 printf("%d is not a prime number.", n);
28 else
29 printf("%d is a prime number.", n);
30}
31