统计期中成绩，为什么会答案错误呢？

Question

Answer 1

cin是C++的
printf是C的，不要混用，而且，这个题目要求输入和输出分开，你这么写不对。
C代码修改如下：

#include <stdio.h>
#include <stdlib.h>
int main()
{
    int m,n,t;
    double *av,*tg;
    int i,j;
    double sum = 0;
    double tongji = 0;
    scanf("%d",&m);
    
    av = (double *)malloc(sizeof(double)*m);
    tg = (double *)malloc(sizeof(double)*m);

    for (i = 0;i<m;i++)
    {
        sum = 0;
        tongji = 0;
        scanf("%d",&n);
        for( j = 0;j<n;j++)
        {
            scanf("%d",&t);
            sum += t;
            if(t >=60)
                tongji++;
        }
        av[i] = sum/n;
        tg[i] = tongji/n;
    }
    for ( i = 0;i<m;i++)
    {
        printf("%.2f %.2f\n",av[i],tg[i]);
    }
    free(av);
    free(tg);
    return 0;
}