How to add function prototypes?

[biscuitownz]

Hi all, I'm new here and needed some assistance regarding this program I'm writing.
I'm trying to make the 2048 in c++ and I'm using switch statements to control movement.

However, I'm not sure how to add a function's prototype return value to an integer variable.

For example, if I have a function prototype declared as int shiftDown();
and I have to later add that function prototype to a variable called move, how would I do that?

This is what I have now, but it does not work.

case 'w':
{
moved = shiftUp();
moved += sumUp();
moved += shiftUp();
}

That was basically my wild guess at it. I've looked around and can't seem to find anything specifically regarding this.

Thanks all.

[kbw]

If the function looks like:

int shiftUp()
{
    // code
}

then the prototype is:

int shiftUp();

[biscuitownz]

When I first declared it, it was just int shiftUp();

Nothing else

EDIT: so If I were to add stuff to it, I would just use

int shiftUp();
{
moved += shiftUp();
}

?

[kbw]

No. That function is calling itself. It's called recursion and is a powerful technique when used appropriately. But you're not using it appropriately.

Why are you making it call itself?

[E0p9LyTq]

However, I'm not sure how to add a function's prototype return value to an integer variable.

http://www.cplusplus.com/doc/tutorial/functions/

http://www.learncpp.com/cpp-tutorial/17-forward-declarations/