#include <stdio.h>
int main()
{
    int s;
    printf("请输入一个成绩：");
    scanf("%d", &s);
    if(s>100 || s < 0)
    {
       printf("输入了一个错误的成绩。\n");
       return 1;
    }
    char ch;
    switch(s/10)
    {
    case 10:
    case 9:   ch = 'A'; break;
    case 8:   ch = 'B'; break;
    case 7:   ch = 'C'; break;
    case 6:   ch = 'D'; break;
    default:
           ch = 'E'; break;
    }
    printf("您输入的成绩等级为：%c\n", ch);
    return 0;
}