Thread: ahh need massive help with this C++ program dealing with calculation of volume/area

I'll start by pointing out this obvious error:

Code:

cin >> "Please select 1-5: " >> selection;

This cannot happen. Cin is supposed to 'read' the user's input. Cout is what the console prints so I'd change it to this.

Code:

cout<<"Please select 1-5";
cin>>selection;

As for the following code:

Code:

void showMenu (int &);

That's a function prototype.
When you define a function after your main code, then you must have a prototype before the main code so it can know it has been defined later on.
It should have the following structure:

Code:

void showMenu(int &)   //<--- Prototype

int main()
{
      showMenu(int &)
      (.........);
}

void showMenu(int &)   //<-- Your function defined
{
    (.....);
}

OR

Code:

void showMenu(int &)  //<-- The function has been defined before main so prototype is not required
{
    (.......);
}

int main()
{
     showMenu(int &);
     (...........);
}

If I was you I'd make a function for each option. One to compute a rectangle area, another for a circle area etc and then call each one of them depending on the user input (1-5).

Btw, the function call is wrong.
Instead of

showMenu(int &);

do

showMenu(your_favorite_int_variable_here);