Operator Ambiguity

[scottman]

Hello!

Forgive me, for I am fairly new to C++, but I am having some trouble regarding operator ambiguity. I think it is compiler-specific, for the code compiled on my desktop. However, it fails to compile on my laptop. I think I know what's going wrong, but I don't see an elegant way around it. Please let me know if I am making an obvious mistake. Anyhow, here's what I'm trying to do:

I have made my own vector class called Vector4 which looks something like this:

class Vector4
{
	private:
		GLfloat vector[4];
	...
}

Then I have these operators, which are causing the problem:

operator GLfloat* () { return vector; }
		
operator const GLfloat* () const { return vector; }

GLfloat& operator [] (const size_t i) { return vector[i]; }

const GLfloat& operator [] (const size_t i) const { return vector[i]; }

I have the conversion operator so that I can pass an instance of my Vector4 class to glVertex3fv, and I have subscripting for obvious reasons. However, calls that involve subscripting the Vector4 become ambiguous to the compiler:

enum {x, y, z, w}
Vector4 v(1.0, 2.0, 3.0, 4.0);

glTranslatef(v[x], v[y], v[z]);

Here are the candidates:

candidate 1: const GLfloat& Vector4:: operator[](size_t) const
candidate 2: operator[](const GLfloat*, int) <built-in>

Why would it try to convert my Vector4 to a GLfloat* first when the subscript operator is already defined on Vector4? Is there a simple way around this? Am I making a silly mistake? Thanks for any help in advance.

Scott