#include
void main(){
char X;
std::cout<<"请输入等级标识"<
switch(X){
case 'A' :std::cout<<">=90"<
case 'B':std::cout<<"80<=且<90"<
case 'C' :std::cout<<"70<=且<80"<
case 'D' :std::cout<<"60<=且<70"<
case 'E' :std::cout<<"<60"<
default :std::cout<<"请输入A~E之间的大写字母"<
}
//希望能帮到你