更好地了解getline（）和cin [英] better understanding of getline() and cin

问题描述

尝试对控制台功能有一些基本的了解。我遇到问题，请考虑以下...

Trying to get some basic understanding of console functionalities. I am having issues so consider the following...

#include "stdafx.h"
#include<iostream>
#include<conio.h>

using namespace std;

/*
This is a template Project
*/

void MultiplicationTable(int x);

int main()
{

    int value = 0;

    printf("Please enter any number \n\n");
    getline(cin, value);

    MultiplicationTable(value);


    getchar();


    return 0;
}

我实际上是基于 http://www.cplusplus.com/doc/tutorial/basic_io/ 。我的IDE不识别getline（）当然，当我编译应用程序。我收到错误

I actually based this off code from http://www.cplusplus.com/doc/tutorial/basic_io/ . My IDE is not recognizing getline() so of course when I compile the application. I get an error

'getline': identifier not found

现在看看这段代码

#include "stdafx.h"
#include<iostream>
#include<conio.h>

using namespace std;

/*
This is a template Project
*/

void MultiplicationTable(int x);

int main()
{

    int value = 0;

    printf("Please enter any number \n\n");
    cin>>value;

    MultiplicationTable(value);


    getchar();


    return 0;
}

当我执行这行代码时，控制台窗口打开并立即关闭。我想我缺少一些关于cin。我知道它定界空间，但我不知道还有什么。我应该使用什么输入，使我的生活更轻松。

When I execute this line of code the console window opens and immediately closes. I think I a missing something about cin. I do know that it delimits spaces but I don't know what else. what should I use for input to make my life easier.

推荐答案

函数 getline（）在字符串头中声明。因此，您必须添加 #include< string> 。
它定义为 istream& getline（istream& is，string& str）; ，但是用 int 而不是字符串对象来调用它。

The function getline() is declared in the string header. So, you have to add #include <string>. It is defined as istream& getline ( istream& is, string& str );, but you call it with an int instead of a string object.

关于您的第二个问题：

当我执行这行代码时，控制台窗口打开，关闭

When I execute this line of code the console window opens and immediately closes

可能还有一个'\\\
'字符输入到流中，当你的程序到达函数 getchar（）（我假设你放在那里，所以你的窗口不关闭）。你必须刷新你的流。一个简单的解决方法是，而不是 getchar（），添加行

There is probably still a '\n' character from your input in the stream, when your program reaches the function getchar() (which I assume you put there so your window doesn't close). You have to flush your stream. An easy fix is, instead of getchar(), add the line

 int c;
 while((c = getchar()) != '\n'){} 

这会清除您的讯息串，直到下一个换行符。

This will flush your stream until the next line-break.

注意： conio.h 的c ++标准和过时。

Remark: conio.h is not part of the c++ standard and obsolete.

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