argv and argc command line params

This is a discussion on argv and argc command line params within the C Programming forums, part of the General Programming Boards category; how do i accept command line parameters onto a program running under windows, i understand argv is the number of ...

  1. #1
    Hamster without a wheel iain's Avatar
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    argv and argc command line params

    how do i accept command line parameters onto a program running under windows, i understand argv is the number of arguements but for eg - if i wanted to accept a 2 as a command line param and act on it - how do i do it.
    tia
    Monday - what a way to spend a seventh of your life

  2. #2
    Registered User
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    i thought argc held the number of arguments where argv held the arguments ??
    "with a gun barrel between your teeth, you speak only in vowels."
    - tyler durden

  3. #3
    &TH of undefined behavior Fordy's Avatar
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    Welcome back!!!!!

    I'm assuming you mean a Win32 Program that uses WinMain???

    If so, the third param of WinMain is a LPSTR which will give you the command line as a string ..

    Also, you can use the GetCommandLine() API at any point to get this data......

    You need some sort of way to tokenise the commandline - so look at strtok from the Std C Library

  4. #4
    Guest Sebastiani's Avatar
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    i thought argc held the number of arguments where argv held the arguments ??
    That is correct. Except that argc will contain number of args + 1, and argv[0] will contain the name of the program.

    The data is in character format, so to extract a number, do:

    int first_arg = atoi(argv[1]);

    But always remember to check the count in argc, if it is 1, then nothing was entered into the command line, and the program should probably exit gracefully

    By the way, the naming convention is arbitrary, you could equally do:

    int main(int count, char* array_of_commands[])
    Code:
    #include <cmath>
    #include <complex>
    bool euler_flip(bool value)
    {
        return std::pow
        (
            std::complex<float>(std::exp(1.0)), 
            std::complex<float>(0, 1) 
            * std::complex<float>(std::atan(1.0)
            *(1 << (value + 2)))
        ).real() < 0;
    }

  5. #5
    End Of Line Hammer's Avatar
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    Code:
    #include <stdio.h>
    
    int main(int argc, char *argv[])
    {
        while (--argc)
            printf ("%s ", *++argv);
        return 0;
    }
    
    
    /* OR */
    
    int main(int argc, char *argv[])
    {
        int i;
        for (i = 1; i < argc; i++)
            puts(argv[i]);
        return 0;
    }
    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

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