闰年测试和对输入的非法判断

#include<stdio.h>
#include<sstream>
#include<string>

using namespace std;

void judge(int year){
bool b;
 if (year % 4 == 0)
         b=true;
 if (year % 100 == 0)
         b=false;
 if (year % 400 == 0)
           b=true;
 if(b==true)
     cout<<"runnian"<<endl;
 if(b!=true)
      cout<<"no runnian"<<endl;
 
}

void judge2(int a)
{
if((a%4==0&&a%100!=0)||(a%400==0))
   cout<<"run nian "<<endl;
else
   cout<<"no run nian";
}

int main(){
 string t;
 int n;
 stingstream ss;
 while(cin>>t){
    ss<<t;
    ss>>n;
    if(!ss.good()){
        cout<<"error";
        break;
    }
    judge(n);
        judge2(n);

 }
 return 0;
}