程序代码：

/* Note:Your choice is C IDE */
#include "stdio.h"
void main()
{
    int num;
    char grade;
    scanf("d",&num);
    num/=10;
    switch(num);
    {
        case 10:
        case 9:
        grade='A';
            printf("%c\n",grade);
        break;
        case 8:
        grade='B';
            printf("%c\n",grade);
        break;
        case 7:
        grade='C';
            printf("%c\n",grade);
        break;
        case 6:
        grade='D';
            printf("%c\n",grade);
        break;
        default:
        grade='E';
            printf("%c\n",grade);
        break;
    }

}