Passing by Reference

[Fransje]

Hi all!
Could someone explain in detail to me what passing by reference actually is, and what the difference is between passing normal variables and passing them by reference? I think it's explained too abstract for me in the tutorial :)
Thanks in advance!

[Script Coder]

Look at following example:

void foo(int value) {
    value++;  //same as value+=1 or value=value+1
}

int main() {
    int myInt;
    myInt=5;
   foo(myInt);
   cout << myInt;
}

this will out put 5, because when you call foo, you pass a copy of myInt, however:

void foo(int& value) {
    value++;  //same as value+=1 or value=value+1
}

int main() {
    int myInt;
    myInt=5;
   foo(myInt);
   cout << myInt;
}

will output 6, because you pass a reference to foo, allowing it to change myInt i.e. passing by reference.


Changed

[Peter87]

In Script Coder's second code line 1 should be void foo(int& value) {

[Script Coder]

Oh sorry, I get confused sometimes, Thank You Peter.

[Fransje]

Thanks, Script Coder! I thought that passing by reference had something to do with variable adresses, but now I got it.

@Peter: I actually don't see any difference. What's different there?

[Script Coder]

@Fransje: Sorry I changed it from a '*' to a '&'