我从来都不记得我是怎么做到的,因为它很少出现在我身上。但是在C或c++中,从标准输入中读取字符而不等待换行符(按enter)的最佳方法是什么?

理想情况下,它也不会将输入字符回显到屏幕上。我只是想在不影响控制台屏幕的情况下捕捉击键。


当前回答

CONIO.H

你需要的函数是:

int getch();
Prototype
    int _getch(void); 
Description
    _getch obtains a character  from stdin. Input is unbuffered, and this
    routine  will  return as  soon as  a character is  available  without 
    waiting for a carriage return. The character is not echoed to stdout.
    _getch bypasses the normal buffering done by getchar and getc. ungetc 
    cannot be used with _getch. 
Synonym
    Function: getch 


int kbhit();
Description
    Checks if a keyboard key has been pressed but not yet read. 
Return Value
    Returns a non-zero value if a key was pressed. Otherwise, returns 0.

libconio http://sourceforge.net/projects/libconio

or

conio.h的Linux c++实现 http://sourceforge.net/projects/linux-conioh

其他回答

CONIO.H

你需要的函数是:

int getch();
Prototype
    int _getch(void); 
Description
    _getch obtains a character  from stdin. Input is unbuffered, and this
    routine  will  return as  soon as  a character is  available  without 
    waiting for a carriage return. The character is not echoed to stdout.
    _getch bypasses the normal buffering done by getchar and getc. ungetc 
    cannot be used with _getch. 
Synonym
    Function: getch 


int kbhit();
Description
    Checks if a keyboard key has been pressed but not yet read. 
Return Value
    Returns a non-zero value if a key was pressed. Otherwise, returns 0.

libconio http://sourceforge.net/projects/libconio

or

conio.h的Linux c++实现 http://sourceforge.net/projects/linux-conioh

这在纯c++中以可移植的方式是不可能的,因为它太依赖于可能与stdin连接的终端(它们通常是行缓冲的)。不过,你可以使用一个库来实现:

conio available with Windows compilers. Use the _getch() function to give you a character without waiting for the Enter key. I'm not a frequent Windows developer, but I've seen my classmates just include <conio.h> and use it. See conio.h at Wikipedia. It lists getch(), which is declared deprecated in Visual C++. curses available for Linux. Compatible curses implementations are available for Windows too. It has also a getch() function. (try man getch to view its manpage). See Curses at Wikipedia.

如果你的目标是跨平台兼容性,我建议你使用curses。也就是说,我相信有一些函数可以用来关闭行缓冲(我相信这被称为“原始模式”,而不是“熟模式”-看看man stty)。如果我没记错的话,诅咒可以方便地帮你解决这个问题。

我也遇到过同样的问题。这里是一个小的解决方案为windows控制台使用cygwing++与if(GetKeyState(keycode) & bitANDcompare){};

#include <windows.h>
#include <fstream>
#include <iostream>

using namespace std;
void clear() {
    COORD topLeft  = { 0, 0 };
    HANDLE console = GetStdHandle(STD_OUTPUT_HANDLE);
    CONSOLE_SCREEN_BUFFER_INFO screen;
    DWORD written;

    GetConsoleScreenBufferInfo(console, &screen);
    FillConsoleOutputCharacterA(
        console, ' ', screen.dwSize.X * screen.dwSize.Y, topLeft, &written
    );
    FillConsoleOutputAttribute(
        console, FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE,
        screen.dwSize.X * screen.dwSize.Y, topLeft, &written
    );
    SetConsoleCursorPosition(console, topLeft);
}

class Keyclick{
    private:
    int key;
    char id;
    public:
    bool keydown = false;
    Keyclick(int key1, char id1){
        key=key1;
        id=id1;
    };
    void watch(){
        if(keydown==false){
            if(GetKeyState(key) & 0x8000 ){
                cout << id;
                cout << "  pressed.\r\n";
                keydown = true;
            }
        }
        if(keydown == true){
            if(!(GetKeyState(key) & 0x8000)) {
                cout << "released!!!!!!!!!!\r\n";
                keydown = false;
                clear();
            }
        }
    };
};

int main()
{
    bool primaryloop =true;
    Keyclick keysp(VK_SPACE,'S');
    Keyclick keyw(0x57,'w');
    Keyclick keya(0x41,'a');
    Keyclick keys(0x53,'s');
    Keyclick keyd(0x44,'d');
    Keyclick keyesc(VK_ESCAPE,'E');
    
    while(primaryloop){
        keysp.watch();
        keyw.watch();
        keya.watch();
        keys.watch();
        keyd.watch();
        keyesc.watch();
        
        if(keyesc.keydown){
            primaryloop=false;
        };      
    }
    return 0;
}

https://github.com/wark77/windows_console_keypoller/blob/main/getkeystate_SOLUTION01.cpp

如果你在windows上,你可以使用PeekConsoleInput来检测是否有任何输入,

HANDLE handle = GetStdHandle(STD_INPUT_HANDLE);
DWORD events;
INPUT_RECORD buffer;
PeekConsoleInput( handle, &buffer, 1, &events );

然后使用ReadConsoleInput“消费”输入字符..

PeekConsoleInput(handle, &buffer, 1, &events);
if(events > 0)
{
    ReadConsoleInput(handle, &buffer, 1, &events);  
    return buffer.Event.KeyEvent.wVirtualKeyCode;
}
else return 0

老实说,这是从一些旧的代码,我有,所以你必须拨弄它一点。

最酷的是它读取输入时没有任何提示,所以字符根本不会显示出来。

C和c++对I/O有一个非常抽象的看法,没有标准的方法来做你想做的事情。有从标准输入流中获取字符的标准方法(如果有的话),这两种语言都没有定义其他任何方法。因此,任何答案都必须是特定于平台的,可能不仅取决于操作系统,还取决于软件框架。

这里有一些合理的猜测,但如果不知道目标环境是什么,就无法回答您的问题。