http://codepad.org/Ae6YM2fK

#include <iostream> using namespace std; int main() { int arr[1000] = {0}, count = 0; for(int i = 2; i < 1000; ++i) { if(arr[i]) { continue; } cout << "P_" << ++count << " = " << i << endl; for(int j = i; j < 1000; j += i) { ++arr[j]; } } return 0; }