Thread: Class prototypes

can you do class prototypes like functions. My problem is that i have two .cpp files and one uses a class from another. i have tile.cpp, which has the class tile, and i have layer.cpp, which has the class layer, which needs to use the class tile. I need to make a header file or something to prototype the classes, can this be done.

just #include your tile.h file in your layer.cpp file. i think that is what you are asking... or you could #include your tile.h file in your layer.h file...(i think that should work)

well i know i could do it that way, but my classes are in .cpp files, and i thought you weren't supposed to #include cpp files, only header files. is there a way to do it this way, or should i just move my classes to header files.

Okay let me clear things up here. You can include a cpp file all you want. The reason why you don't is because it can make your project confusing for others to understand. Also no one suggested that you do so. Here is a very basic example here.

myheader.h

Code:

class MyClass {
public:
    int GetValue(void) const;
private:
    int value;
}

myclass.cpp

Code:

include "myheader.h"

int MyClass::GetValue(void)  {
    return this->value;
}

main.cpp

Code:

#include "myheader.h"
#include <iostream>
using namespace std;

int main(void) {
    MyClass x;
    cout << x.GetValue();
    return 0;
}

Of course since MyClass::value is never initialized running this may end up breaking the program but now you know what alpha was talking about.

There is also something called forword referencing. It is like prototyping for classes.

Code:

class myarray;
class my2darray {
public:
    myarray array;
};

class myarray {
public:
    my2darray array;
};

This is a horrible example of why this could be necessary but just put this little bit of knowledge in the back of your brain for when you need it.