Thread: Console Application

  1. #1
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    Console Application

    So I'm writing a console application for dos and such, and I wrote this while loop such that I keep asking for the correct input, you know validating correct inputs, well all i wanted to was when the user gave me the incorrect input they would reenter the data. The problem is I only want to prompt the user once, and I don't won't to scroll down another line, is it possible to delete the input that was entried? My only solution was to use for loops some escape commands, reposted the same prompts, and wa-lah! any suggestions, if i can't do it go ahead and say so, I've been told i can't do several things b4.

  2. #2
    Frequently Quite Prolix dwks's Avatar
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    Once the user has entered a newline, you have no way to scroll up a line without using escape sequences or some other platform-dependent method.

    You could use getch() or another non-standard unbuffered input function to read your input instead.

    Is there any reason that you don't want the screen to scroll?
    dwk

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    eh, no reason besides looks.
    getch() what does that do? which header is it from? sorry that I ask I'm pretty new to programming

  4. #4
    Frequently Quite Prolix dwks's Avatar
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    Note the word non-standard. Your compiler might not have it; if you're using Dev-C++ or an old DOS compiler, you might. If you do, it's usually in <conio.h>. http://faq.cprogramming.com/cgi-bin/...&id=1043284392

    To get getch() to do what you want, check for an enter (which is '\r' with getch()), sort of like this: http://board.theprogrammingsite.com/viewtopic.php?t=143
    dwk

    Seek and ye shall find. quaere et invenies.

    "Simplicity does not precede complexity, but follows it." -- Alan Perlis
    "Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
    "The only real mistake is the one from which we learn nothing." -- John Powell


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  5. #5
    MFC killed my cat! manutd's Avatar
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    You could also clear the screen and then re output the prompt.
    Silence is better than unmeaning words.
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  6. #6
    Frequently Quite Prolix dwks's Avatar
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    To do so: http://faq.cprogramming.com/cgi-bin/...&id=1043284385

    If there's other stuff on the screen, it might be difficult to repaint the screen:
    Code:
    Enter your name: dwks
    Enter your type: wizard
    Enter your starting level: one
    dwk

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  7. #7
    MFC killed my cat! manutd's Avatar
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    Given that he's showed no code, it's hard to tell...
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    But when i ask for an input with cin, and press enter, won't my screen automatically scroll down another line or so?, So I can't exactly retrace, or can I? i just don't know is it possible. But as for manutd, are you suggesting using the ms-dos command cls, clear screen. I''ve exactly learned how to use dos functions within my code. How would I go about doing that, I've been interested in doing that also.

  9. #9
    and the hat of int overfl Salem's Avatar
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    It's all the more difficult without knowing which OS and Compiler is being used.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    may i say them(sorry bout that), Microsoft Visual .Net and WINDOWS XP PRO ...yada

  11. #11
    MFC killed my cat! manutd's Avatar
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    Try system("CLS").
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  12. #12
    Frequently Quite Prolix dwks's Avatar
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    It's in the FAQ I posted.

    system() is a function in <stdlib.h>; it executes a system command, which for Windows is a DOS command.

    You might also be able to set the cursor position on the screen, again with a non-standard function: http://faq.cprogramming.com/cgi-bin/...&id=1043284392
    dwk

    Seek and ye shall find. quaere et invenies.

    "Simplicity does not precede complexity, but follows it." -- Alan Perlis
    "Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
    "The only real mistake is the one from which we learn nothing." -- John Powell


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    My website: http://dwks.theprogrammingsite.com/
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