#include<stdio.h>

int main()

{

int score;

L1:printf("请输入你的成绩为：");

scanf("%d",&score);

if(score>=0&&score<=100)

switch( score/10)

{

case 10:

    case 9:

printf("等级A\n");break;

case 8:

printf("等级B\n");break;

case 7:

case 6:

printf("等级C\n");break;

default:

printf("等级D\n");break;

}

else

printf("您输入的数有误！请重新输入！\n");

goto L1;

return 0;

}