c语言解决成绩等级划分问题，出现错误

#include<stdio.h>
int main()
{
int score;
printf("输入成绩:");
scanf("%d",&score);
score=score/10;
switch('score')
{
case '10':printf("A");break;
case '9':printf("A");break;
case '8':printf("B");break;
case '7':printf("C");break;
case '6':printf("D");break;
default:printf("E\n");
}
return 0;
}

//单引号都要去掉，不然就是字符了
switch(score)
{
case 10:printf("A");break;
case 9:printf("A");break;
case 8:printf("B");break;
case 7:printf("C");break;
case 6:printf("D");break;
default:printf("E\n");
}