Functions with multiple definitions

This is a discussion on Functions with multiple definitions within the C Programming forums, part of the General Programming Boards category; Hello All, I'm really rusty in C/C++ and was wondering how you declare a function that can take multiple data ...

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    Question Functions with multiple definitions

    Hello All,

    I'm really rusty in C/C++ and was wondering how you declare a function that can take multiple data types as parameters. For instance, lets say you were making your own print function that could accept a string or an integer as an input parameter. I remember doing this in a programming class a while back but there was some way that you do the function definition so that you make two different functions, one to handle the string input and another one to handle the integer but they both have the same name.... What is that called again and is that used in C or only C++?

    Thanks,
    Jason O

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    spurious conceit MK27's Avatar
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    It's called a template -- you can also google "generic programming", and it is only available in C++.

    Depending on exactly what you want to do, you may probably be able to do it in C using void pointers and an extra param to indicate type.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

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    Well, no. The actual mechanism is function overloading. Declare and define two functions with the same name but different argument types.

    Template functions provide one method of achieving function overloading, in the case where the definition of the function is applicable to multiple types.

    Both templates and function overloading are C++ specific.
    Right 98% of the time, and don't care about the other 3%.

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    spurious conceit MK27's Avatar
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    Sorry, grumpy is correct. The difference between using a template and overloading a function is that without a template, the function must be defined multiple times. With a template, you can write one single function definition to cover multiple cases.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

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    Ahhh ok! Overloading was the term I was looking for. Thank you!!

    - Jason O

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