错误输出:,后面要有一个空格
printf("%.2lf",maxprice);
cout<<","<<max_s<<endl;
printf("%.2lf",minprice);
cout<<","<<min_s<<endl;
正确输出：
printf("%.2lf",maxprice);
cout<<", "<<max_s<<endl;
printf("%.2lf",minprice);
cout<<", "<<min_s<<endl;

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int main(){
    int n;
    double price,maxprice=0,minprice=0;
    cin>>n;
    getchar();
    string s,max_s,min_s;
    for(int i=1;i<=n;i++){
        getline(cin,s);
        cin>>price;
        getchar();
    //    cout<<"sadad"<<price;
        if(i==1){
            maxprice=price;
            minprice=price;
            max_s=s;
            min_s=s;
        }else{
            //cout<<price<<"   "<<maxprice<<"    "<<minprice<<endl;
            if(price>maxprice){
                maxprice=price;max_s=s;
            }
            if(minprice>price){
                //cout<<"min"<<minprice<<price<<endl;
                minprice=price;min_s=s;
            }
        }
    }
    printf("%.2lf",maxprice);
    cout<<", "<<max_s<<endl;
    printf("%.2lf",minprice);
    cout<<", "<<min_s<<endl;
}