Return values and pointers

This is a discussion on Return values and pointers within the C++ Programming forums, part of the General Programming Boards category; I am curious on how the return values work. I know the basics. Code: int x; int getMyInt() { return ...

  1. #1
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    Return values and pointers

    I am curious on how the return values work.

    I know the basics.

    Code:
    int x;
    
    int getMyInt() {
    return x;
    }
    
    void test() {
    modify(getMyInt());
    }
    
    void modify(int y) {
    y = 3;
    }
    Can someone explain how the data flow works here?

  2. #2
    Algorithm Dissector iMalc's Avatar
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    'modify' has no effect on the variable passed into it because you are passing by value.
    To see why y is just a copy of the parameter, consider that it is perfectly okay to do:
    Code:
    modify(42);
    This clearly does not make 42 equal to 3.

    What you want is to pass by reference.
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