/* H3, Opdracht 17 - list primes 2 - 100 */
#include <stdio.h>
#include <math.h>
	main ()
	{
		int n;
		printf("%d", 2);
		
		/* trick: by adding two we skip the even numbers */
		for (n = 3; n < 100; n+=2)
		{
			if (isPrime(n) == 1)
				printf("%d", n);
		}
	}
	
	int isPrime (int n)
	{
		int i;
		
		/* trick: we only need to check for divisability until the root of n */
		// for (i = 3; i < Math.sqrt(n); i++)
		for (i = 3; i < (n / 2); i+=2)
		{
			if (n % i == 0)
				return 0;
		}
		
		/* gee, this number must be prime */
		return 1;
	}