與正確輸出不相符(line:21)
您的答案為: 非質數
正確答案為: 質數

 我已經試過千百遍

除非我知道測資的值，不然我永遠也不知道問題在哪...

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
    int a,b,c;
    while (cin>>a){
          c=sqrt((double)a);
          for (b=2;b<=c;b++){
              if (a%b==0){
                 cout<<"非質數\n";
                 break;
                 }
              while (b==c){
                    if (a%b!=0){
                       cout<<"質數\n";
                       break;
                       }    
                   
                    }
          }     
    }
    return 0;
}