Need help: wait for key press

This is a discussion on Need help: wait for key press within the C++ Programming forums, part of the General Programming Boards category; I'm implementing the function that lets user set the control keys of the game. After the user clicks, it will ...

  1. #1
    Pan
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    Need help: wait for key press

    I'm implementing the function that lets user set the control keys of the game. After the user clicks, it will wait until one key is pressed (without enter). I use kbhit() to wait for key press like this.

    Code:
    while(!kbhit()){}
    But even a key is pressed, it doesn't exit the loop. What's wrong with this?

    Appreciate all your help.

  2. #2
    and the hat of int overfl Salem's Avatar
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    Well you neglected to tell us which OS and Compiler you're using.

    How about the FAQ?
    http://faq.cprogramming.com/cgi-bin/...&id=1043284392
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
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    Pan
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    I use VC++ 2003 on Windows

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    Lightbulb

    i have had slightly the same problem hours ago.
    i use the "Dev-C++ (Bloodshed) vers. 4.9.8.0" on a Windows XP machine.
    Code:
    if(kbhit())
    {
      i++;
    }
    instead of just executing the i++ one time it went on and on...

    so someone came up with this solution:
    kbhit() reads the keystroke into the buffer and doesn't
    delete it afterwards. a "fflush(stdin)" doesn't do the job, so a "getch()" is definitly necessary here.

    Code:
    if(kbhit())
    {
     getch();
      i++;
    }
    i'm sorry for any spelling mistakes for i am not a native speaker...

  5. #5
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    kbhit() only checks if a key has been pressed, getch() will return it's value. Also do note that these are conio.h functions and are outside of standard C.
    Code:
    #include <stdio.h>
    
    void J(char*a){int f,i=0,c='1';for(;a[i]!='0';++i)if(i==81){
    puts(a);return;}for(;c<='9';++c){for(f=0;f<9;++f)if(a[i-i%27+i%9
    /3*3+f/3*9+f%3]==c||a[i%9+f*9]==c||a[i-i%9+f]==c)goto e;a[i]=c;J(a);a[i]
    ='0';e:;}}int main(int c,char**v){int t=0;if(c>1){for(;v[1][
    t];++t);if(t==81){J(v[1]);return 0;}}puts("sudoku [0-9]{81}");return 1;}

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