假设是Windows，看一下ReadConsoleInput函数。

下面是一个不向系统提供外壳的版本(在macOS 10.14上编写和测试)

#include <unistd.h>
#include <termios.h>
#include <stdio.h>
#include <string.h>

char* getStr( char* buffer , int maxRead ) {
  int  numRead  = 0;
  char ch;

  struct termios old = {0};
  struct termios new = {0};
  if( tcgetattr( 0 , &old ) < 0 )        perror( "tcgetattr() old settings" );
  if( tcgetattr( 0 , &new ) < 0 )        perror( "tcgetaart() new settings" );
  cfmakeraw( &new );
  if( tcsetattr( 0 , TCSADRAIN , &new ) < 0 ) perror( "tcssetattr makeraw new" );

  for( int i = 0 ; i < maxRead ; i++)  {
    ch = getchar();
    switch( ch )  {
      case EOF: 
      case '\n':
      case '\r':
        goto exit_getStr;
        break;

      default:
        printf( "%1c" , ch );
        buffer[ numRead++ ] = ch;
        if( numRead >= maxRead )  {
          goto exit_getStr;
        }
        break;
    }
  }

exit_getStr:
  if( tcsetattr( 0 , TCSADRAIN , &old) < 0)   perror ("tcsetattr reset to old" );
  printf( "\n" );   
  return buffer;
}


int main( void ) 
{
  const int maxChars = 20;
  char      stringBuffer[ maxChars+1 ];
  memset(   stringBuffer , 0 , maxChars+1 ); // initialize to 0

  printf( "enter a string: ");
  getStr( stringBuffer , maxChars );
  printf( "you entered: [%s]\n" , stringBuffer );
}

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;
}

我总是想要一个循环读取我的输入而不按返回键。 这对我很管用。

#include<stdio.h>
 main()
 {
   char ch;
    system("stty raw");//seting the terminal in raw mode
    while(1)
     {
     ch=getchar();
      if(ch=='~'){          //terminate or come out of raw mode on "~" pressed
      system("stty cooked");
     //while(1);//you may still run the code 
     exit(0); //or terminate
     }
       printf("you pressed %c\n ",ch);  //write rest code here
      }

    }

Ncurses提供了一个很好的方法来做到这一点! 这也是我的第一篇文章(我记得)，所以欢迎任何评论。我会欣赏有用的，但都是受欢迎的!

编译： g++ -std=c++11 -pthread -lncurses .cpp -o

#include <iostream>
#include <ncurses.h>
#include <future>

char get_keyboard_input();

int main(int argc, char *argv[])
{
    initscr();
    raw();
    noecho();
    keypad(stdscr,true);

    auto f = std::async(std::launch::async, get_keyboard_input);
    while (f.wait_for(std::chrono::milliseconds(20)) != std::future_status::ready)
    {
        // do some work
    }

    endwin();
    std::cout << "returned: " << f.get() << std::endl;
    return 0;
}

char get_keyboard_input()
{
    char input = '0';
    while(input != 'q')
    {
        input = getch();
    }
    return input;
}

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。