c++结构体输出5个学生平均成绩和3科平均成绩以及平均分最高的学生数据 编译不通过 不知道哪里错了 想知道怎么改

Question

#include<bits/stdc++.h>
using namespace std;
struct student{
    char name[20];
    double score[3];
    double stuavg[5];
}stu[5];
void input(){
    for(int i=0;i<5;i++){
    cout<<"please input the student's name"<<endl;
    cin>>stu[i].name;
    cout<<"please input the student's scores for the three cources"<<endl;
    cin>>stu[i].score[0]>>stu[i].score[1]>>stu[i].score[2];
}
} 
void cal1(struct student *stu){//计算每个学生的平均分 
    for(int i=0;i<5;i++){
        stu[i].stuavg=(stu[i].score[0]+stu[i].score[1]+stu[i].score[2])/3.0;
        printf("NO %d 's avrage score is %lf",i+1,stu[i].stuavg);
}
}
void cal2(struct student *stu){//计算每门课的平均分 
     double courseavg[3];
     for(int i=0;i<3;i++){
         for(int j=0;j<5;j++){
         courseavg[i]=stu[j].score[0];
         courseavg[i]/=5.0;
     }
    printf("The average score of this course is %lld",courseavg[i]);
}
} 
void beststu(){
    int i;
    for(i=0;i<4;i++){
        if(stu[i].stuavg<stu[i++].stuavg){
            stu[i].stuavg=stu[i++].stuavg;
            int k;
            i=k;
        }
    } 
    cout<<stu[i].name<<endl;
    cout<<stu[i].score[0]<<endl;
    cout<<stu[i].score[1]<<endl;
    cout<<stu[i].score[2]<<endl;
}
int main(){
    input();
    cal1();
    cal2();
    beststu();
}