main to function question

This is a discussion on main to function question within the C++ Programming forums, part of the General Programming Boards category; How would I import the variables from main to a function without passing it to the function? In the example ...

  1. #1
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    Sep 2007
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    main to function question

    How would I import the variables from main to a function without passing it to the function? In the example my teacher gave me, he only passed 3 items to the function, but used variables from the main in the function without passing it and did not declare them in the function. How is this possible?

    very rough example:
    Code:
    void example(stuff, stuff2, stuff3)
    {
    blah;
    blah2=stuff;
    blah3=hello;
    hello = stuff;
    }
    
    void main()
    {
    blah;
    blah2;
    char hello;
    int stuff, stuff2, stuff3;
    hello = blah;
    example(stuff, stuff2, stuff3);
    }
    Last edited by Rice; 09-18-2007 at 03:40 PM.

  2. #2
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    Ok, I just called my teacher and he told me why. He declared them globally and I guess I didn't catch that in my notes.

  3. #3
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    If the variables are global then you can use them in main and in any other function.

    If the variables are local to a function, then the only way to use them or their values in another function is to pass them as arguments or return them.

    Generally global variables are not good design. Of course, a teacher who teaches void main() (it should be int main()) might also be teaching global variables even if their use is a bad idea, so that makes sense that it's your answer.

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