Question

求C语言题目：请输入星期几的第一个字母来判断一下是星期几,如果第一个字母一样,则继续判断第二个字母

#include<stdio.h>
int main()
{
char week1;
char week2;
printf("please enter a letter\n");
scanf("%c",&week1);
switch(week1)
{
case'M':printf("the answer is Monday\n");
break;
case'W':printf("the answer is Wednesday\n");
break;
case'F':printf("the answer is Friday\n");
break;
case'S':
{
printf("please enter the second letter\n");
scanf("%c",&week2);
if(week2=='a')
printf("the answer is Saturday\n");
else
if(week2=='u')
printf("the answer is Sunday\n");
else
printf("there is no answer\n");
}
break;
case'T':
{
printf("please enter the second letter\n");
scanf("%c",&week2);
if(week2=='u')
printf("the answer is Tuesday\n");
else
if(week2=='h')
printf("the answer is Thursday\n");
else
printf("there is no answer\n");
}
break;
default:
printf("there is no correct answer\n");
break;
}
return 0;
}
在输入第二个字母时出问题？是怎么回事？求指教

Answer 1

在scanf("%c",&week1);

后加一个清除缓冲区；

fflush(stdin)

Answer 2

用scanf时当你输入一个字符过后再输入回车，下次再用scanf时，上次输入的回车会直接被当作字符输入，所以你不能进行第二次输入。像楼上所说，在scanf之后加上fflush（stdin）就可以清空缓冲区了~

Answer 3

在 scanf("%c",&week1); 下加一句：
getchar();

追问

亲，能解释一下为什么吗？

追答

输入一个字符加回车，scanf("%c",&week1);只能接收一个字符，回车还留在输入流中，被scanf("%c",&week2);接收。加getchar()可以接收这个回车，这样到scanf("%c",&week2);时就可以重新输入了。楼下的也可以。