#include<stdlib.h>
void main()
{
    struct grade
    {
        int C;
        char name[20];
        char course[20];
        int score;
        char degree;
        int no;
    };
    struct grade *student;
    int i;
    int num;
    char degree[][10] = {"不及格", "及格", "中等", "良好", "优秀"};
    int statistics[5] = {0};
    int distribution[11] = {0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 4};
    float sum = 0.0;
    printf("请输入学生人数 ==>");
    scanf("%d",&num);
    student=(struct grade *)malloc(num *sizeof(struct grade));
    if(!student)
    {
        printf("内存分配失败 !\n");
        exit(1);
    }
    for(i=0;i<num;i++)
    {
      //printf("学生编号: %d\n",i + 1);     
      printf("请输入学生编号. ==> ");
      scanf("%s",&student[i].no);
      printf("请输入学生姓名. ==> ");
      scanf("%s",&student[i].name[i]);      
      printf("请输入你要查询的课程. ==> ");
      scanf("%s",&student[i].course );
      printf("请输入成绩. ==> ");
      scanf("%d",&student[i].C);     
    }
        for (i = 0; i < num; i++)
   {
       sum += student[i].C;
     }

     printf("\n平均分：%.2f\n\n", sum / num);
    for (i = 0; i < num; i++)
        statistics[distribution[(int)(student[i].C / 10)]]++;

    printf("等级统计：\n");
    for (i = 0; i < 5; i++)
    printf("%s:\t%d人\t%.1f%%\n", degree[i], statistics[i], 100 * (float)statistics[i]/num);
}