Write a program in C to check whether a number is a prime number or not using the function

#include <stdio.h>
int main() 
{
	int n, i, count=0;
	printf("Enter a positive integer: ");
	scanf("%d", &n);
	for (i =1; i <=n; ++i) 
	{
		if (n% i== 0) 
		{
			++count;
		}
	}
	if (count==2)
		printf("%d is a prime number.", n);
	else
		printf("%d is not a prime number.", n);
	return 0;
}