Is there a way to detect if a key has been pressed?

问题

I am compiling and executing my programs in cygwin on a windows computer. I am quite inexperienced in C but I would like a way to detect if a key has been pressed without prompting the user(e.g me). My pseudo code with desirable functions is shown below.

char ch;
while(1){
    if(KeyBeenPressed()){
    //a key has been pressed before getting here
        ch=getKeyPressed();
        if(ch=='0'){
            printf("you have pressed 0");
        }
        else{
            printf("you did't press key 0");
        }
    }

//do other stuff
}

And my own try to solving this after searching the web is shown below.

#include <stdio.h>
#include <conio.h>
char ch;
void main(){
    while(1){
        if(kbhit()){ //kbhit is 1 if a key has been pressed
            ch=getch();
            printf("pressed key was: %c", ch);
        }
    }
}

A problem with this code is that the conio.h file can't be found(and I haven't found any other way to solve this). Apparently gcc compilers can't handle conio.h(I have attached the link to were it stood). http://www.programmingsimplified.com/c/conio.h

So I wonder if any of you guys know a way to detect if a key has been pressed in C, I would also like to retrieve the pressed key preferably in a char (I plan on using 0-9 for this application). The important thing is that the program can't wait until a key is pressed.

I am thankful for any suggestions that could solve this! Best regards Henrik

回答1:

I use the following function for kbhit(). It works fine on g++ compiler in Ubuntu.

#include <termios.h>
#include <unistd.h>
#include <fcntl.h>
int kbhit(void)
{
  struct termios oldt, newt;
  int ch;
  int oldf;

  tcgetattr(STDIN_FILENO, &oldt);
  newt = oldt;
  newt.c_lflag &= ~(ICANON | ECHO);
  tcsetattr(STDIN_FILENO, TCSANOW, &newt);
  oldf = fcntl(STDIN_FILENO, F_GETFL, 0);
  fcntl(STDIN_FILENO, F_SETFL, oldf | O_NONBLOCK);

  ch = getchar();

  tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
  fcntl(STDIN_FILENO, F_SETFL, oldf);

  if(ch != EOF)
  {
    ungetc(ch, stdin);
    return 1;
  }

  return 0;
}

回答2:

Most of Dos, Windows 3.x or win32 platform provide the file conio.h, but unix or linux Os is not provide this file normally. If you use unix or linux Os , you must download it on the internet By yourself. i hope my answer is useful for you.

来源：https://stackoverflow.com/questions/22166074/is-there-a-way-to-detect-if-a-key-has-been-pressed

标签

windows

keyboard

keypress

detection