Functions with variable argument count..

This is a discussion on Functions with variable argument count.. within the C++ Programming forums, part of the General Programming Boards category; I'm wondering if there is a way to deal with functions that can have a variable number of arguments passed ...

  1. #1
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    Functions with variable argument count..

    I'm wondering if there is a way to deal with functions that can have a variable number of arguments passed to it. I already know of va_* functions but it doesn't seem that good. I was hoping there would be some way to restrict the data type to one data type, and also have random access to the arguments (va_* doesn't seem to have random access, unless you iterate through and copy it all to your own array first). It also seems that the va_* only works for basic data types and not my own class that i made.

    Something like this:

    Code:
    std::string FormatString(const std::string& format, int num, const Variable* varList, ...)
    {
    }
    Where "num" is the number of arguments passed and "varList" is an array of the arguments.

    EDIT: err...nvm about the example, but is there any other methods for variable functions arguments? Would you have to use asm or something?
    Last edited by 39ster; 04-11-2009 at 09:06 AM.

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by 39ster
    I was hoping there would be some way to restrict the data type to one data type, and also have random access to the arguments
    You could make the parameter a std::vector.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    I suppose i could. Anyways a little bit more looking around and i found out that variable arguments are alot more restrictive than i thought. I thought the program would pass "int num" but it turns out you have to pass that manually =D

    It would be cool if the example i gave could be possible though (as in, "varList" holds all the arguments proceeding "const std::string& format" and "int num" would the amount of elements in varList)

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by 39ster
    It would be cool if the example i gave could be possible though (as in, "varList" holds all the arguments proceeding "const std::string& format" and "int num" would the amount of elements in varList)
    Take a look at how Boost.Format does it.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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