getch

This is a discussion on getch within the C Programming forums, part of the General Programming Boards category; I am in the process of writing an old invaders game of sorts. When I ran into a problem, I ...

  1. #1
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    getch

    I am in the process of writing an old invaders game of sorts. When I ran into a problem, I was using

    Code:
    key = getch ( );
    switch ( key )
    {
    case '4':
    //go left
    break;
    
    case '6':
    //go right
    break;
    
    case '8':
    //go up
    break;
    
    case '2':
    //go down
    break;
    }
    when I realized then when I reach the getch statement, my programs halts. And waits for user input, that is a very serious problem. How can I get around this.

    p:s: the enemy ships and their bullets only move when I move.

  2. #2
    Dr Dipshi++ mike_g's Avatar
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    You need an event checking method. I only know how to do this using SDL_PollEvent, which requires (surprise) SDL. A friend of mine once made a console based space invaders game. So it is possible. I don't know how, but I would be interested to find out.

  3. #3
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    in visual basic there is a keypress command, does C have a similar command that doesnt halt the program?

  4. #4
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    aside from learning another language, any other ideas?

  5. #5
    Kernel hacker
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    The function for checking the "is there anything from the keyboard" is system and compiler dependant, but give "kbhit()" a try - it may work, depending on what environment you are programming in. It won't work under Linux, that's for sure.

    --
    Mats

  6. #6
    Deathray Engineer MacGyver's Avatar
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    Try learning the O/S you're writing this for or a library that covers this stuff.

  7. #7
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    >p:s: the enemy ships and their bullets only move when I move.
    One idea is to use kbhit() to check whether a key has been pressed.
    Code:
    if (kbhit())
    {
    	key = getch ( );
    	switch ( key )
    	{
    	case '4':
    	//go left
    	break;
    
    	case '6':
    	//go right
    	break;
    
    	case '8':
    	//go up
    	break;
    
    	case '2':
    	//go down
    	break;
    	}
    }
    /* Other code */

  8. #8
    Registered User MacNilly's Avatar
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    Yup and linux doesn't have kbhit() so u could use the ncurses library (or graphics library of your choice) to detect for a keystroke... It's in any good game library, just a matter of finding it,

  9. #9
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    kbhit is a step in the right direction. But now if I hit the left key, my ship keeps moving left until I till it to go somewhere else.

  10. #10
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    in other words its acting like a toggle switch without the off command.

  11. #11
    and the hat of wrongness Salem's Avatar
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    Post some more code, in particular the whole loop containing moving commands, kbhit() and getch() calls.
    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.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  12. #12
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    swoopy has posted the code already.

  13. #13
    and the hat of wrongness Salem's Avatar
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    So you have no code to move any object outside of the block guarded by if ( kbhit() ) ?
    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.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  14. #14
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    The actual code is over 3000 characters , I am just working on the movement system as of now. And right now when I hit the left movement key, it keeps on moving until I change the direction.

    *edit*

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