getchar 接收字符的时候

#include <stdio.h>
#include <stdlib.h>

int main()
{
int x,y;
char ch;
while(scanf("%d",&x)==1)
{
ch = getchar();
while(ch==' '){ ch = getchar();}
scanf("%d",&y);
switch(ch)
{
case '+':printf("%d ",x+y);break;
case '-':printf("%d ",x-y);break;
case '*':printf("%d ",x*y);break;
default : break;
}
}
return 0;
}

1. 在按回车前，getchar在等待，getchar()函数在按下回车后从输入缓冲区读取1个字符