Pointers vs. References in C++ function arguments [duplicate]

Question

I was wondering how to make a function alter two variables (the return and another one) and I stumbled upon calling the function with an '&' before the parameter (which I understand to mean the address of the parameter) then throughout your function, referencing it with the '*' sign (which I guess is a "dereference" and means it alters the object at the address).

Anyways, this was all going fine, then a friend said you can just call the function with the variable directly, refer to the variable with an & before it in the header, and treat it normally throughout the function. This seems way easier, so why isn't there more about it on the web? Is one style more correct than the other?

void foo(int &junk)  //The way the friend said
{
    junk++;
}

void oof(int *junk) //what I found, and what the internet seems full of
{
    (*junk)++;
}

int main ()
{
    int junk=1;
    std::cout << junk << "\n";
    foo(junk);
    std::cout << junk << "\n";
    oof(&junk);
    std::cout << junk;
}

This outputs:

1
2
3

So everything works fine, I'd assume.

Answer 1

The you first function foo, you are passing by reference :

When a variable is passed by reference we are not passing a copy of its value, but we are somehow passing the variable itself to the function and any modification that we do to the local variables will have an effect in their counterpart variables passed as arguments in the call to the function.

An example of passing by reference :

In your second example oof, you are passing a pointer to the variable.

If you want to know the different between both example, I suggest you to read this : https://stackoverflow.com/a/57492/1394283

But, When you should use references and when you should use pointer ?

I will say use references whenever you can, use pointers whenever you must.

The reason is that pointers makes things harder to follow/read, less safe and far more dangerous manipulations than any other constructs.

This post explains it very well : https://stackoverflow.com/a/7058373/1394283