#include <stdio.h>
void main()
{
int n;
printf("please input :");
scanf("%d",&n);
switch(n)
{case 1:if("85<n<=100")
printf("A");break;
case 2:if("70<n<=85")
printf("B");break;
case 3:if("60<n<=70")
printf("C");break;
case 4:if("n<=60")
printf("D");break;
default:printf("error\n");
}
}


怎么总是出现error呢