1 ，基本的选择语句的使用switch
int score;
while(score != 100){//放到下面的
printf("输入你的分数:\n");
scanf("%d",&score);
if(score < 0 || score > 100){
printf("你输入的分数不合法:\n");
continue;//结束本次循环，进行下一次的循环
}
else {
int rank = (int)score/10;
switch(rank){
case 9: printf("your rank is A");
break;
case 8: printf("your rank is B");
break;
case 7: printf("your rank is C");
break;
case 6: printf("your rank is D");
break;
default: printf("your rank is E");
}
}
}
return 0;
