我为什么错了？90分

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
struct stu {
    string name;
    int chinese=0,math=0,english=0;
    int sum = 0;
};
bool comp(stu a,stu b){//排序函数 
    return a.sum>b.sum;
}
int main(){
    int n;
    cin>>n;
    stu a[n+1];
    for(int i=1;i<=n;i++){//输入 
        cin>>a[i].name;
        cin>>a[i].chinese;
        cin>>a[i].math;
        cin>>a[i].english;
        a[i].sum = a[i].chinese + a[i].math +a[i].english ;
    }
    sort(a+1,a+n+1,comp);//排序 
    //输出 
    cout<<a[1].name<<" "<<a[1].chinese<<" "<<a[1].math<<" "<<a[1].english ;
    cout<<endl;
    return 0;
}