3-5

#include<stdio.h>
int main(void)
{
    char op;
    printf("输入五级制成绩:");
    scanf("%c",&op);
    switch(op){
        case'A':printf("grade=90-100");
            break;
        case'B':printf("grade=80-89");
            break;
        case'C':printf("grade=70-79");
            break;
        case'D':printf("grade=60-69");
            break;
        case'E':printf("grade=0-59");
            break;
    }
    return 0;
}