运行结果异常，哪儿错了呢

运行结果错误，哪儿错了呢？
题目是编写程序，从输入文件“data.in”中读入某班n个学生信息，建立学生数据结构体，包括学号、姓名和三门课的成绩，计算输出该班各门课的平均分。

我的编码是编写程序

#include<stdio.h>
int main()
{
struct st{
  char num[10];
  char name[30];
  unsigned int scores[3];
  };
unsigned int scores[3];
float aver;
int i, sum, n;
struct st stu[3];
FILE *fp = fopen("data2.in", "r");
if(fp==NULL){
  printf("error 1\n");
  return 1;
}
fscanf(fp, "%d", &n);
if(n <=1||n>=60){
  printf("error 2\n");
  return 2;
}
for(i = 0; i <n; i++)
{
  fscanf(fp, "%s %s %d %d %d", &stu[i].num, &stu[i].name, &stu[0].scores[i], &stu[1].scores[i], &stu[2].scores[i]);
  sum==stu[0].scores[i]+stu[1].scores[i]+stu[3].scores[i];
  aver==sum%3;
  printf("math:%d\n, English:%d\n, C-progra:%d\n");
}
fclose(fp);
return 0;
}


[解决办法]

C/C++ code

        sum==stu[0].scores[i]+stu[1].scores[i]+stu[3].scores[i];        aver==sum%3;