高手指教一下，getchar()的问题

[筋斗云王]

#include<iostream>
using namespace std;
int main()
{
cout<<"please input two numbers"<<endl;
int num1,num2,max,min,count=0;
//输出num1,num2
cout<<"before input current num is:"<<num1<<" "<<num2<<endl;
cin>>num1>>num2;

cout<<"after input current num is:"<<num1<<" "<<num2<<endl;

getchar();//暂停一下（如果输入的不是两个规范数，比如说是字母，在这里不会停顿）

//判断输入的两个数的大小
if(num1>=num2)
{
max=num1;
min=num2;
}
else
{
max=num2;
min=num1;
}
//按每行不超过十个数来输出给定的两个数之间的数
for(int i=min;i<=max;i++,count++)
{
if(count!=0&&count%10==0)
{
cout<<endl;
count=0;
}
cout<<i<<" ";

}
getchar();
return 0;
}

[HelloDan]

#include <iostream>
using namespace std;
int main()
{
    cout <<"please input two numbers" <<endl;
    int num1,num2,max,min,count=0;
//输出num1,num2
    cout <<"before input current num is:" <<num1 <<" " <<num2 <<endl;
    cin>> num1>> num2;
    
    cout <<"after input current num is:" <<num1 <<" " <<num2 <<endl;
    
	fflush(stdin);
    getchar();//暂停一下（如果输入的不是两个规范数，比如说是字母，在这里不会停顿）

//判断输入的两个数的大小
  if(num1>=num2)
    {
max=num1;
        min=num2;
    }
    else
    {
max=num2;
        min=num1;
    }
//按每行不超过十个数来输出给定的两个数之间的数
    for(int i=min;i <=max;i++,count++)
    {
        if(count!=0&&count%10==0)
        {
   cout <<endl;
           count=0;
        }
   cout <<i <<" ";
        
    }  
    getchar();
    return 0;
}

int getchar ( void );



<cstdio>

Get character from stdin

Returns the next character from the standard input (stdin).
It is equivalent to getc with stdin as its argument.

Return Value
The character read is returned as an int value.
If the End Of File is reached or a reading error happens, the function returns EOF and the corresponding error or eof indicator is set. You can use either ferror or feof to determine whether an error happened or the End-Of-File was reached.

[Michael_555]

如果你输入的不是数字，例如输入了英文字符，
cin> > num1> > num2不会从输入缓冲里面将输入的内容取出来的。
这样getchar()的时候，看到输入缓冲里面还有内容，就会直接取出一个字符，而不会停下来等待输入了。

[Michael_555]

运行一下这段代码，你就知道原因了

#include <iostream> 
using namespace std; 
int main() 
{
    int num = 0;
    char ch;

    cout<<"input a number num="<<endl;
    cin>>num;

    ch = getchar();
    cout<<"inputed number is"<<num<<endl;
    cout<<"input character is"<<ch<<endl;

    return 0;
}

在显示input a number num=的时候输入
a
就会自动输出，不会对num做输入的
0， a