Semi-noob Q: calling functions

This is a discussion on Semi-noob Q: calling functions within the C++ Programming forums, part of the General Programming Boards category; What is the point of calling a function? I'm currently reading Sam's teach yourself C++ and its discussing functions. In ...

  1. #1
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    Semi-noob Q: calling functions

    What is the point of calling a function? I'm currently reading Sam's teach yourself C++ and its discussing functions. In a sample program, the function is first declared using prototypes. Then it is called using main and then the function is executed. Does calling a function activate it? Thanks for help.

  2. #2
    mustang benny bennyandthejets's Avatar
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    Yes, calling a function executes the code contained within it. Functions are used to seperate code into more efficient blocks. If you had, say, a block of code which is executed many times during a program, instead of writing the same code in many times, you just place it in a function, and then call that function whenever you need to execute its code. Here is a trivial example:
    Code:
    int MultiplyTwoNumbers(int FirstNumber,int SecondNumber)
    {
        return (FirstNumber * SecondNumber);
    }
    
    int main()
    {
        int Answer=MultiplyTwoNumbers(5,7);
    
        return Answer;
    }
    Here, a function, 'MultiplyTwoNumbers', is defined, and it takes two ints as parameters and returns an int. This means that the int 'Answer' will be assigned the value 5*7 =35.

    Make sure to only use functions to avoid heavy repetitions of code, or to encapsulate a certain activity.
    benforbes@optusnet.com.au
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  3. #3
    Carnivore ('-'v) Hunter2's Avatar
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    Actually, given the question "What is the point of calling a function", I don't think that was a good example But consider functions like std::cin.getline(). It would be a big pain in the rear if every time you wanted to get input you had to type out the code for getline(). In short, functions are used to simplify a program, so you don't have to do this:
    Code:
    //Read a character from the user
    int a = 239as7f@#ajflksjfa;
    faobiu(213.z;aWEr0as
    fjskldafl213#3(f23");
    fsdafjlke
    3289a7sdeFSJALK
    fsjlakwejf
     
    //Read another character from the user
    int a = 239as7f@#ajflksjfa;
    faobiu(213.z;aWEr0as
    fjskldafl213#3(f23");
    fsdafjlke
    3289a7sdeFSJALK
    fsjlakwejf
    **EDIT** Hmm, actually I guess "What's the point of" could also be read as "What does _x_ mean?"... If that's the case, read benny's post and ignore mine
    Just Google It. √

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