我使用kbhit()来查看是否存在一个字符，然后使用getchar()来读取数据。 在windows上，您可以使用“conio.h”。在linux上，您必须实现自己的kbhit()。

参见下面的代码:

// kbhit
#include <stdio.h>
#include <sys/ioctl.h> // For FIONREAD
#include <termios.h>
#include <stdbool.h>

int kbhit(void) {
    static bool initflag = false;
    static const int STDIN = 0;

    if (!initflag) {
        // Use termios to turn off line buffering
        struct termios term;
        tcgetattr(STDIN, &term);
        term.c_lflag &= ~ICANON;
        tcsetattr(STDIN, TCSANOW, &term);
        setbuf(stdin, NULL);
        initflag = true;
    }

    int nbbytes;
    ioctl(STDIN, FIONREAD, &nbbytes);  // 0 is STDIN
    return nbbytes;
}

// main
#include <unistd.h>

int main(int argc, char** argv) {
    char c;
    //setbuf(stdout, NULL); // Optional: No buffering.
    //setbuf(stdin, NULL);  // Optional: No buffering.
    printf("Press key");
    while (!kbhit()) {
        printf(".");
        fflush(stdout);
        sleep(1);
    }
    c = getchar();
    printf("\nChar received:%c\n", c);
    printf("Done.\n");

    return 0;
}

最接近可移植的方法是使用ncurses库将终端置于“cbreak模式”。API是巨大的;你最想要的是

Initscr和endwin 黄昏时分和黄昏时分 getch

好运！

由于这里之前的解决方案不能跨平台工作，并且在特殊键上存在问题，所以这里是我的解决方案，它在Windows和Linux上都可以工作，并且使用了最少的外部库(Windows.h和Linux的sys/ioctl.h+termios.h)。

对于ASCII字符(换行符/tab/space/backspace/delete， !"#$%&'()*+，-./0-9:;<=>?@A-Z[]^_ ' a-z{|}~üäÄöÖÜßµ´§°¹³)，返回ASCII码(正数);对于特殊键(方向键、上页/下页、pos1/end、转义、插入、F1-F12)，返回Windows虚拟键码(负数)的负数。

#include <iostream>
#include <string>
#include <thread> // contains <chrono>
using namespace std;

void println(const string& s="") {
    cout << s << endl;
}
void sleep(const double t) {
    if(t>0.0) this_thread::sleep_for(chrono::milliseconds((int)(1E3*t+0.5)));
}



// ASCII codes (key>0): 8 backspace, 9 tab, 10 newline, 27 escape, 127 delete, !"#$%&'()*+,-./0-9:;<=>?@A-Z[]^_`a-z{|}~üäÄöÖÜßµ´§°¹³²
// control key codes (key<0): -38/-40/-37/-39 up/down/left/right arrow, -33/-34 page up/down, -36/-35 pos1/end
// other key codes (key<0): -45 insert, -144 num lock, -20 caps lock, -91 windows key, -93 kontext menu key, -112 to -123 F1 to F12
// not working: ¹ (251), num lock (-144), caps lock (-20), windows key (-91), kontext menu key (-93), F11 (-122)
#if defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
#define VC_EXTRALEAN
#include <Windows.h>
int key_press() { // not working: F11 (-122, toggles fullscreen)
    KEY_EVENT_RECORD keyevent;
    INPUT_RECORD irec;
    DWORD events;
    while(true) {
        ReadConsoleInput(GetStdHandle(STD_INPUT_HANDLE), &irec, 1, &events);
        if(irec.EventType==KEY_EVENT&&((KEY_EVENT_RECORD&)irec.Event).bKeyDown) {
            keyevent = (KEY_EVENT_RECORD&)irec.Event;
            const int ca = (int)keyevent.uChar.AsciiChar;
            const int cv = (int)keyevent.wVirtualKeyCode;
            const int key = ca==0 ? -cv : ca+(ca>0?0:256);
            switch(key) {
                case  -16: continue; // disable Shift
                case  -17: continue; // disable Ctrl / AltGr
                case  -18: continue; // disable Alt / AltGr
                case -220: continue; // disable first detection of "^" key (not "^" symbol)
                case -221: continue; // disable first detection of "`" key (not "`" symbol)
                case -191: continue; // disable AltGr + "#"
                case  -52: continue; // disable AltGr + "4"
                case  -53: continue; // disable AltGr + "5"
                case  -54: continue; // disable AltGr + "6"
                case  -12: continue; // disable num block 5 with num lock deactivated
                case   13: return  10; // enter
                case  -46: return 127; // delete
                case  -49: return 251; // ¹
                case    0: continue;
                case    1: continue; // disable Ctrl + a (selects all text)
                case    2: continue; // disable Ctrl + b
                case    3: continue; // disable Ctrl + c (terminates program)
                case    4: continue; // disable Ctrl + d
                case    5: continue; // disable Ctrl + e
                case    6: continue; // disable Ctrl + f (opens search)
                case    7: continue; // disable Ctrl + g
                //case    8: continue; // disable Ctrl + h (ascii for backspace)
                //case    9: continue; // disable Ctrl + i (ascii for tab)
                case   10: continue; // disable Ctrl + j
                case   11: continue; // disable Ctrl + k
                case   12: continue; // disable Ctrl + l
                //case   13: continue; // disable Ctrl + m (breaks console, ascii for new line)
                case   14: continue; // disable Ctrl + n
                case   15: continue; // disable Ctrl + o
                case   16: continue; // disable Ctrl + p
                case   17: continue; // disable Ctrl + q
                case   18: continue; // disable Ctrl + r
                case   19: continue; // disable Ctrl + s
                case   20: continue; // disable Ctrl + t
                case   21: continue; // disable Ctrl + u
                case   22: continue; // disable Ctrl + v (inserts clipboard)
                case   23: continue; // disable Ctrl + w
                case   24: continue; // disable Ctrl + x
                case   25: continue; // disable Ctrl + y
                case   26: continue; // disable Ctrl + z
                default: return key; // any other ASCII/virtual character
            }
        }
    }
}
#elif defined(__linux__)
#include <sys/ioctl.h>
#include <termios.h>
int key_press() { // not working: ¹ (251), num lock (-144), caps lock (-20), windows key (-91), kontext menu key (-93)
    struct termios term;
    tcgetattr(0, &term);
    while(true) {
        term.c_lflag &= ~(ICANON|ECHO); // turn off line buffering and echoing
        tcsetattr(0, TCSANOW, &term);
        int nbbytes;
        ioctl(0, FIONREAD, &nbbytes); // 0 is STDIN
        while(!nbbytes) {
            sleep(0.01);
            fflush(stdout);
            ioctl(0, FIONREAD, &nbbytes); // 0 is STDIN
        }
        int key = (int)getchar();
        if(key==27||key==194||key==195) { // escape, 194/195 is escape for °ß´äöüÄÖÜ
            key = (int)getchar();
            if(key==91) { // [ following escape
                key = (int)getchar(); // get code of next char after \e[
                if(key==49) { // F5-F8
                    key = 62+(int)getchar(); // 53, 55-57
                    if(key==115) key++; // F5 code is too low by 1
                    getchar(); // take in following ~ (126), but discard code
                } else if(key==50) { // insert or F9-F12
                    key = (int)getchar();
                    if(key==126) { // insert
                        key = 45;
                    } else { // F9-F12
                        key += 71; // 48, 49, 51, 52
                        if(key<121) key++; // F11 and F12 are too low by 1
                        getchar(); // take in following ~ (126), but discard code
                    }
                } else if(key==51||key==53||key==54) { // delete, page up/down
                    getchar(); // take in following ~ (126), but discard code
                }
            } else if(key==79) { // F1-F4
                key = 32+(int)getchar(); // 80-83
            }
            key = -key; // use negative numbers for escaped keys
        }
        term.c_lflag |= (ICANON|ECHO); // turn on line buffering and echoing
        tcsetattr(0, TCSANOW, &term);
        switch(key) {
            case  127: return   8; // backspace
            case  -27: return  27; // escape
            case  -51: return 127; // delete
            case -164: return 132; // ä
            case -182: return 148; // ö
            case -188: return 129; // ü
            case -132: return 142; // Ä
            case -150: return 153; // Ö
            case -156: return 154; // Ü
            case -159: return 225; // ß
            case -181: return 230; // µ
            case -167: return 245; // §
            case -176: return 248; // °
            case -178: return 253; // ²
            case -179: return 252; // ³
            case -180: return 239; // ´
            case  -65: return -38; // up arrow
            case  -66: return -40; // down arrow
            case  -68: return -37; // left arrow
            case  -67: return -39; // right arrow
            case  -53: return -33; // page up
            case  -54: return -34; // page down
            case  -72: return -36; // pos1
            case  -70: return -35; // end
            case    0: continue;
            case    1: continue; // disable Ctrl + a
            case    2: continue; // disable Ctrl + b
            case    3: continue; // disable Ctrl + c (terminates program)
            case    4: continue; // disable Ctrl + d
            case    5: continue; // disable Ctrl + e
            case    6: continue; // disable Ctrl + f
            case    7: continue; // disable Ctrl + g
            case    8: continue; // disable Ctrl + h
            //case    9: continue; // disable Ctrl + i (ascii for tab)
            //case   10: continue; // disable Ctrl + j (ascii for new line)
            case   11: continue; // disable Ctrl + k
            case   12: continue; // disable Ctrl + l
            case   13: continue; // disable Ctrl + m
            case   14: continue; // disable Ctrl + n
            case   15: continue; // disable Ctrl + o
            case   16: continue; // disable Ctrl + p
            case   17: continue; // disable Ctrl + q
            case   18: continue; // disable Ctrl + r
            case   19: continue; // disable Ctrl + s
            case   20: continue; // disable Ctrl + t
            case   21: continue; // disable Ctrl + u
            case   22: continue; // disable Ctrl + v
            case   23: continue; // disable Ctrl + w
            case   24: continue; // disable Ctrl + x
            case   25: continue; // disable Ctrl + y
            case   26: continue; // disable Ctrl + z (terminates program)
            default: return key; // any other ASCII character
        }
    }
}
#endif // Windows/Linux

最后，这里有一个如何使用它的例子:

int main() {
    while(true) {
        const int key = key_press(); // blocks until a key is pressed
        println("Input is: "+to_string(key)+", \""+(char)key+"\"");
    }
    return 0;
}

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

适用于我的windows:

#include <conio.h>
char c = _getch();

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。