Thread: Constructor Overloading

Folks,

I'm having a strange problem where I can't seem to get my program recognise my overloaded constructors. I've declared 2 constructors, one with 6 parameters and then another with 8 parameters as below:-

Code:

SPRITE(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index, float x = 1, float y = 1, int i_lives = 1); //constructor

SPRITE(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index, float x = 1, float y = 1, int i_lives = 1, bool frozen = true, double frozen_end_time = 0);

SPRITE::SPRITE(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index, float x, float y, int i_lives)
{
	draw_area = draw_engine_ptr;
	pos.x = x;
	pos.y = y;
	sprite_index = s_index;
	num_lives = i_lives;

	facing_dir.x=1;
	facing_dir.y=0;

	classID = SPRITE_CLASSID;

	level_ptr = l_ptr;
                frozen = false;
	frozen_end_time = 0;

}

SPRITE::SPRITE(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index, float x, float y, int i_lives, bool new_frozen, double new_frozen_end_time)
{

	draw_area = draw_engine_ptr;
	pos.x = x;
	pos.y = y;
	sprite_index = s_index;
	num_lives = i_lives;

	facing_dir.x=1;
	facing_dir.y=0;

	classID = SPRITE_CLASSID;

	level_ptr = l_ptr;
	frozen = new_frozen;
	frozen_end_time = new_frozen_end_time;
}

Now I've got several classes that inherit from this SPRITE class and the majority of them only need to pass into the SPRITE constructor with 6 parameters like below:-

Code:

class CHARACTER : public SPRITE
{

public:

	CHARACTER(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index, float x = 1, float y = 1, int lives = 3,
		char up_key = 'w', char down_key = 's', char left_key = 'a', char right_key = 'd');

protected:
	
	char up_key;
	char down_key; 
	char left_key;
	char right_key;
};

CHARACTER::CHARACTER(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index, float x, float y, int lives,
		char up, char down, char left, char right)
		: SPRITE(l_ptr, draw_engine_ptr, s_index, x, y,lives)
{
	
	up_key = up; 
	down_key = down; 
	left_key = left; 
	right_key = right;

	classID = CHARACTER_CLASSID;
}

};

Now I'm explictly calling the SPRITE constructor that has 6 parameters but I keep getting the error:-

error C2668: 'SPRITE::SPRITE' : ambiguous call to overloaded function

Isn't it possible to overload constructors with different parameters ? I've re-checked to ensure that I'm passing in the correct parameters type's etc and all looks good.

Any ideas ?

Cheers
Starkhorn

hmm. think I got it. Both my constructors had the exact same first 6 parameters which I think made it impossible for the compiler to know which constructor to call.

I changed my 2nd constructor to:-

Code:

SPRITE(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index, bool frozen = true, double frozen_end_time = 0, float x = 1, float y = 1, int i_lives = 1);

SPRITE::SPRITE(LEVEL *l_ptr, DRAW_ENGINE *draw_engine_ptr, int s_index,  bool new_frozen, double new_frozen_end_time, float x, float y, int i_lives)
{

	draw_area = draw_engine_ptr;
	pos.x = x;
	pos.y = y;
	sprite_index = s_index;
	num_lives = i_lives;

	facing_dir.x=1;
	facing_dir.y=0;

	classID = SPRITE_CLASSID;

	level_ptr = l_ptr;
	frozen = new_frozen;
	frozen_end_time = new_frozen_end_time;
}

And it compiled without those errors.