素数

#define N 32
#include <iostream>
//#include <stdio.h>
//using namespace std;
main() {
	int i, j, a[N];

	for ( i = 2; i < N; i++ ) {
		a[i] = 1;
	}	

	for ( i = 2; i < N; i++  ) {
		if ( a[i] ) {
			for( j = i; i*j < N; j++ ) {
				a[i*j] = 0;
			}
		}
	}

	for ( i = 2; i < N; i++ ) {
		if( a[i] ) {
			printf( "%4d", i );
		}
	}
	printf("\n");
	system("pause");
}