#include <stdio.h>

void main(){
    char a,b,c;
    do{
        printf("input the grade");
        scanf("%c",&c);
        switch(c){
        case 'A':case 'a': printf("wonderful");
            break;
        case 'B':case 'b':printf("good");
            break;
        case 'C':case 'c':printf("soso");
            break;
        case 'D':case 'd':printf("bad");
            break;
        default:
            printf("wrong");
            break;
        }
                printf("more student?(y to continue");
        scanf("%c",&a);
    }while(a!='y');
}

这个程序会跳过more students 的验证，求指教为什么啊