Hello everybody,

I have a few questions regarding C++ as it is new to me.
Finally I have made the step after 7 years of Java programming to C++.
The thing is that Java made me a die hard OOP minded programmer (where I think C++ and I won't be the best friends because of that)

I am a bit confused about the C++ OOP methods (as it is 90% the same but the approach is different).
The thing I'm trying to achieve is to create a global struct array variable that I can call & adjust.
But on the return tmpSq; I get a few errors that I don't understand at all
Is the difference in OOP that big between Java and C++ that it's a profession on it's own? Or did I miss something?

Square.h

struct CUSTOMVERTEX {FLOAT X, Y, Z, RHW; DWORD COLOR;};
CUSTOMVERTEX *square[];



Square.cpp

void main()
{
*square = getSquareArray(p);
}

CUSTOMVERTEX* getSquareArray(POINT p)
{
CUSTOMVERTEX tmpSq[] =
{
// First triangle
{ p.X, p.Y, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 255, 0), },
{ p.X + DIMENSION, p.Y, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 255, 0), },
{ p.X + DIMENSION, p.Y + DIMENSION, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 255, 0), },
// Second triangle
{ p.X -2 + DIMENSION, p.Y + DIMENSION, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 255, 0), },
{ p.X -2, p.Y + DIMENSION, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 255, 0), },
{ p.X -2, p.Y, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 255, 0), },
};

return tmpSq;
}


Aswell requesting an object thru a method is not possible? Like so:

CUSTOMVERTEX square[] = getSquareArray(p);


Thanks in advanced.
Yours sincerely,

Nyllian

There are several problems with that code, none of which have anything to do with OOP. Here are three of them:
* A name that is all capitals usually denotes a macro (which you should try to avoid, by the way), so CUSTOMVERTEX might confuse people.
* You probably want square to be an array of objects, not an array of pointers, and you probably shouldn't get used to using global variables.
* You can't return an array from a function in C++.
* `void main()' is not a valid prototype for main(). If you learned that from a book, throw the book away and get one that is less than 12 years old.

Here is a complete standard program that does similar things to what you were trying to do:
#include <iostream>

typedef unsigned u32;

u32 make_color(unsigned char r, unsigned char g, unsigned char b) {
return (r << 16) + (g << 8) + b;
}

struct Point2D {
float x, y;
Point2D(float x, float y)
: x(x), y(y) {
}
};

struct CustomVertex {
float x, y, z, rhw;
u32 color;

CustomVertex() {
}

CustomVertex(float x, float y, float z, float rhw, u32 color)
: x(x), y(y), z(z), rhw(rhw), color(color) {
}
};

void getSquareArray(CustomVertex square[6], Point2D p, float side) {
u32 yellow = make_color(255, 255, 0);

// First triangle

square[0] = CustomVertex(p.x , p.y , 0.5f, 1.0f, yellow);
square[1] = CustomVertex(p.x + side, p.y , 0.5f, 1.0f, yellow);
square[2] = CustomVertex(p.x + side, p.y + side, 0.5f, 1.0f, yellow);

// Second triangle
square[3] = square[2];
square[4] = CustomVertex(p.x , p.y + side, 0.5f, 1.0f, yellow);
square[5] = square[0];
}

int main() {
Point2D p(3.0f,4.0f);
CustomVertex square[6];

getSquareArray(square, p, 10.0f);

for (int i=0; i<6; ++i) {
std::cout << '(' << square.x
<< ',' << square.y
<< ',' << square.z
<< ") " << square.rhw
<< " (" << square.color
<< ")\n";
}
}


This is just a portion of code, it's actually the basic of the whole concept.
And the book was 14 years old, wich I allready have thrown away.

I understand the logic of your code alvaro. It actually makes perfect sense now I look at it.
You give the variable to the function that will set the variable instead of calling a returning method. (If I get it right)

and the `void main()` was loosly written out of hand but you get the picture.

Thanks for correcting me and pointing me to a proper pathway.
Yours truly,

Nyllian