a007. 判斷質數 | From: [122.116.5.186] | 發表日期 : 2009-05-04 21:00

#include<iostream>
#include<math.h>

using namespace std;

int check(int num){
  if(num%2 == 0 && num != 2) return true;
  int i,run;
  run = ceil(sqrt(num));
  for(i = 3;i <= run;i+=2){
    if(num%i == 0) return true;
    return false;
  }
}

int main(){
  int a;
  while(cin >> a){
    if(check(a)){
      cout << "非質數" << endl;
    }else{
      cout << "質數" << endl;
    }
  }
}