If you need to pass by reference instead of value, use the referencing operator in the function declaration, instead of sending a reference at call time. Like so:

becomes:

References will not create a copy of the variable being sent, but instead use the memory handle of that variable to manipulate it. I don't know if there is actually more to know about them, but the fact that a reference to a variable points to the same variable, where as a copy points to another, different, variable (changing the reference affects the original variable, changing the copy does not).

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