哪里错了

#include<cstdio>
#include<iostream>
#include<math.h>
using namespace std;
typedef struct stu{
    int Chinese;
    int Math;
    int English;
}Stu[1024];
Stu stu[1024];
int sum[1024];
void Solution(Stu *stu,int num){
    int count=0;
    for(int i=1;i<=num;i++){
        //int sum=0;
        for(int j=i+1;j<=num;j++){//第i个学生开始与他后面的学生比成绩
            if(abs(stu[i]->Chinese-stu[j]->Chinese)<=5&&abs(stu[i]->Math-stu[j]->Math)<=5&&abs(stu[i]->English-stu[j]->English)<=5
            &&abs(stu[i]->Chinese+stu[i]->Math+stu[i]->English-stu[j]->Chinese+stu[j]->Math+stu[j]->English)<=10){
                count++;//旗鼓相当
            }
        }
    }printf("%d",count);
    
}
int main(){
    int num;
    scanf("%d",&num);
    for(int i=1;i<=num;i++){
        scanf("%d%d%d",&stu[i]->Chinese,&stu[i]->Math,&stu[i]->English);
    }
    
    Solution(stu,num);
    return 0;
}

为什么打印出来的是0？根据样例 我到底哪里不对？