输入一个考试成绩，90～100输出A，80～90输出B，70～80输出C，60～70输出D，60以下输出E
代码：
＃include<stdio.h>
int main()
{
float score;
printf("Enter a score:");
scanf("%f",&score);
int n;
n=score/10;
switch(n){
case 10:
case 9:
printf("A ");
break;
case 8:
printf("B ");
break;
case 7:
printf("C ");
break;
case 6:
printf("D ");
break;
case 5:
case 4:
case 3:
case 2:
case 1:
case 0:
printf("E ");
break;
}
}
default子句可以省略不用