Unhandled exceptions, pointers and objects :(

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Interplanetary Funk

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Joined: 19th Apr 2010

Location: Ipswich, United Kingdom

Posted: 31st Jan 2011 00:07

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Hey, I'm having a problem with the following code:

//Include DarkGDK :)
#include "DarkGDK.h"

//Structs
struct _Ability
{
	//Assign the ability callback function
	int(*Ability_CallBack)(int ID, int Ability_Level);

int cost_MP, cost_HP, cost_CD, ID, Ability_Level;

int Pull(int ID)
	{
		return Ability_CallBack(ID, Ability_Level);
	}
};

struct _Character
{
	int HP_Base, MP_Base, HP_pl, MP_pl;
	_Ability Ability1, Ability2, Ability3, Ability4;
	int ModelID;
};

struct _Player
{
	int HP_Bonus, MP_Bonus, HP_Curr, MP_Curr;
	int x, y, TeamID;
	_Character &Character;
};

//Globals
/*Characters*/
_Character* Steph = new _Character;

/*Players*/
_Player* Player1;

//Function Prototypes
/*World*/
void MakeWorld();

/*Abilities*/
int Abilities(int ID, int Ability_Level);

/*Net*/
int Connect();
int UpdatePlayers();
int GetServerMessages();

/*Make Chars*/
void MakeCharacters()
{
	dbMakeObjectSphere(1, 5, 4, 4);
	Steph->HP_Base = 400;
	Steph->MP_Base = 250;

Steph->HP_pl = 75;
	Steph->MP_pl = 50;

Steph->ModelID = 1;

Steph->Ability1.ID = 1;
	Steph->Ability2.ID = 2;
	Steph->Ability3.ID = 3;
	Steph->Ability3.ID = 4;

Steph->Ability1.cost_CD = 10;
	Steph->Ability2.cost_CD = 20;
	Steph->Ability3.cost_CD = 30;
	Steph->Ability4.cost_CD = 40;
	
	Steph->Ability1.cost_HP = 0;
	Steph->Ability2.cost_HP = 0;
	Steph->Ability3.cost_HP = 0;
	Steph->Ability4.cost_HP = 0;

Steph->Ability1.cost_MP = 10;
	Steph->Ability2.cost_MP = 20;
	Steph->Ability3.cost_MP = 30;
	Steph->Ability4.cost_MP = 40;

Steph->Ability1.Ability_Level = 1;
	Steph->Ability2.Ability_Level = 2;
	Steph->Ability3.Ability_Level = 3;
	Steph->Ability4.Ability_Level = 4;

Steph->Ability1.Ability_CallBack = &Abilities;
	Steph->Ability2.Ability_CallBack = &Abilities;
	Steph->Ability3.Ability_CallBack = &Abilities;
	Steph->Ability4.Ability_CallBack = &Abilities;
}

//Entry point
void DarkGDK(void)
{
	Player1->Character=*Steph;
	Player1->TeamID = 1;

dbPrint(dbStr(Player1->Character.Ability1.Ability_Level));

dbWaitKey();
}

int Abilities(int ID, int Ability_Level)
{
	dbPrint(dbStr(ID));
	dbPrint(dbStr(Ability_Level));
	return 0;
}

+ Code Snippet

//Include DarkGDK :)
#include "DarkGDK.h"

//Structs
struct _Ability
{
	//Assign the ability callback function
	int(*Ability_CallBack)(int ID, int Ability_Level);

	int cost_MP, cost_HP, cost_CD, ID, Ability_Level;

	int Pull(int ID)
	{
		return Ability_CallBack(ID, Ability_Level);
	}
};

struct _Character
{
	int HP_Base, MP_Base, HP_pl, MP_pl;
	_Ability Ability1, Ability2, Ability3, Ability4;
	int ModelID;
};

struct _Player
{
	int HP_Bonus, MP_Bonus, HP_Curr, MP_Curr;
	int x, y, TeamID;
	_Character &Character;
};

//Globals
/*Characters*/
_Character* Steph = new _Character;

/*Players*/
_Player* Player1;

//Function Prototypes
/*World*/
void MakeWorld();

/*Abilities*/
int Abilities(int ID, int Ability_Level);

/*Net*/
int Connect();
int UpdatePlayers();
int GetServerMessages();

/*Make Chars*/
void MakeCharacters()
{
	dbMakeObjectSphere(1, 5, 4, 4);
	Steph->HP_Base = 400;
	Steph->MP_Base = 250;

	Steph->HP_pl = 75;
	Steph->MP_pl = 50;

	Steph->ModelID = 1;

	Steph->Ability1.ID = 1;
	Steph->Ability2.ID = 2;
	Steph->Ability3.ID = 3;
	Steph->Ability3.ID = 4;

	Steph->Ability1.cost_CD = 10;
	Steph->Ability2.cost_CD = 20;
	Steph->Ability3.cost_CD = 30;
	Steph->Ability4.cost_CD = 40;
	
	Steph->Ability1.cost_HP = 0;
	Steph->Ability2.cost_HP = 0;
	Steph->Ability3.cost_HP = 0;
	Steph->Ability4.cost_HP = 0;

	Steph->Ability1.cost_MP = 10;
	Steph->Ability2.cost_MP = 20;
	Steph->Ability3.cost_MP = 30;
	Steph->Ability4.cost_MP = 40;

	Steph->Ability1.Ability_Level = 1;
	Steph->Ability2.Ability_Level = 2;
	Steph->Ability3.Ability_Level = 3;
	Steph->Ability4.Ability_Level = 4;

	Steph->Ability1.Ability_CallBack = &Abilities;
	Steph->Ability2.Ability_CallBack = &Abilities;
	Steph->Ability3.Ability_CallBack = &Abilities;
	Steph->Ability4.Ability_CallBack = &Abilities;
}

//Entry point
void DarkGDK(void)
{
	Player1->Character=*Steph;
	Player1->TeamID = 1;

	dbPrint(dbStr(Player1->Character.Ability1.Ability_Level));

	dbWaitKey();
}

int Abilities(int ID, int Ability_Level)
{
	dbPrint(dbStr(ID));
	dbPrint(dbStr(Ability_Level));
	return 0;
}

It compiles fine but I get an unhandled exception error whenever I run the exe (debug or release) without giving me any useful information back. The problem seems to be this line:

Quote: "Player1->Character=*Steph;"

I honestly have no idea what I'm doing wrong as it compiles 100% fine.

I'm using visual studio 8 (2005) and the commercial version of darkGDK.

thanks in advance for any replies.

BASIC programmers never die, they GOSUB and don't RETURN.

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JTK

14

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Joined: 10th Feb 2010

Location:

Posted: 31st Jan 2011 01:27 Edited at: 31st Jan 2011 01:31

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And it will compile fine, if that is indeed the line causing the error. I have not compiled it but it does make sense...

In this case, "Player1->Character" is expecting a-pointer to an object of type _Character (_Character*). In many cases, that would mean prepending the & (address of) operator before the assignment when you create a variable of type _Character. However, you don't create a variable of type _Character, you are creating a variable of type (pointer-to) _Character (_Character*) with the new command. This means that the variable Steph is already a pointer, so by the line you are using, you are saying "assign the pointer to the address in memory that holds the address of the Steph object". In effect, you are assigning the pointer-to-a-pointer.

In short, remove the * operator before Steph and you will be assigning the pointer that it is expecting.

Don't forget to release the associated memory with the call to "delete Steph" before program exit!

JTK

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Interplanetary Funk

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Years of Service

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Joined: 19th Apr 2010

Location: Ipswich, United Kingdom

Posted: 31st Jan 2011 01:35 Edited at: 31st Jan 2011 01:35

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OK, I've changed my code to the following:

//Include DarkGDK :)
#include "DarkGDK.h"

//Structs
struct _Ability
{
	//Assign the ability callback function
	int(*Ability_CallBack)(int ID, int Ability_Level);

int cost_MP, cost_HP, cost_CD, ID, Ability_Level;

int Pull(int ID)
	{
		return Ability_CallBack(ID, Ability_Level);
	}
};

struct _Character
{
	int HP_Base, MP_Base, HP_pl, MP_pl;
	_Ability Ability1, Ability2, Ability3, Ability4;
	int ModelID;
};

struct _Player
{
	int HP_Bonus, MP_Bonus, HP_Curr, MP_Curr;
	_Character &Character;
	int x, y, TeamID;
};

//Globals
/*Characters*/
_Character Steph;

/*Players*/
_Player Player1;

//Function Prototypes
/*World*/
//void MakeWorld();

/*Abilities*/
int Abilities(int ID, int Ability_Level);

/*Net*/
//int Connect();
//int UpdatePlayers();
//int GetServerMessages();

/*Make Chars*/
void MakeCharacters()
{
	dbMakeObjectSphere(1, 5, 4, 4);
	Steph.HP_Base = 400;
	Steph.MP_Base = 250;

Steph.HP_pl = 75;
	Steph.MP_pl = 50;

Steph.ModelID = 1;

Steph.Ability1.ID = 1;
	Steph.Ability2.ID = 2;
	Steph.Ability3.ID = 3;
	Steph.Ability3.ID = 4;

Steph.Ability1.cost_CD = 10;
	Steph.Ability2.cost_CD = 20;
	Steph.Ability3.cost_CD = 30;
	Steph.Ability4.cost_CD = 40;
	
	Steph.Ability1.cost_HP = 0;
	Steph.Ability2.cost_HP = 0;
	Steph.Ability3.cost_HP = 0;
	Steph.Ability4.cost_HP = 0;

Steph.Ability1.cost_MP = 10;
	Steph.Ability2.cost_MP = 20;
	Steph.Ability3.cost_MP = 30;
	Steph.Ability4.cost_MP = 40;

Steph.Ability1.Ability_Level = 1;
	Steph.Ability2.Ability_Level = 2;
	Steph.Ability3.Ability_Level = 3;
	Steph.Ability4.Ability_Level = 4;

Steph.Ability1.Ability_CallBack = &Abilities;
	Steph.Ability2.Ability_CallBack = &Abilities;
	Steph.Ability3.Ability_CallBack = &Abilities;
	Steph.Ability4.Ability_CallBack = &Abilities;
}

//Entry point
void DarkGDK(void)
{
	Player1.Character=Steph;
	Player1.TeamID = 1;

dbPrint(dbStr(Player1.Character.Ability1.Ability_Level));

dbWaitKey();
}

int Abilities(int ID, int Ability_Level)
{
	dbPrint(dbStr(ID));
	dbPrint(dbStr(Ability_Level));
	return 0;
}

+ Code Snippet

//Include DarkGDK :)
#include "DarkGDK.h"

//Structs
struct _Ability
{
	//Assign the ability callback function
	int(*Ability_CallBack)(int ID, int Ability_Level);

	int cost_MP, cost_HP, cost_CD, ID, Ability_Level;

	int Pull(int ID)
	{
		return Ability_CallBack(ID, Ability_Level);
	}
};

struct _Character
{
	int HP_Base, MP_Base, HP_pl, MP_pl;
	_Ability Ability1, Ability2, Ability3, Ability4;
	int ModelID;
};

struct _Player
{
	int HP_Bonus, MP_Bonus, HP_Curr, MP_Curr;
	_Character &Character;
	int x, y, TeamID;
};

//Globals
/*Characters*/
_Character Steph;

/*Players*/
_Player Player1;

//Function Prototypes
/*World*/
//void MakeWorld();

/*Abilities*/
int Abilities(int ID, int Ability_Level);

/*Net*/
//int Connect();
//int UpdatePlayers();
//int GetServerMessages();

/*Make Chars*/
void MakeCharacters()
{
	dbMakeObjectSphere(1, 5, 4, 4);
	Steph.HP_Base = 400;
	Steph.MP_Base = 250;

	Steph.HP_pl = 75;
	Steph.MP_pl = 50;

	Steph.ModelID = 1;

	Steph.Ability1.ID = 1;
	Steph.Ability2.ID = 2;
	Steph.Ability3.ID = 3;
	Steph.Ability3.ID = 4;

	Steph.Ability1.cost_CD = 10;
	Steph.Ability2.cost_CD = 20;
	Steph.Ability3.cost_CD = 30;
	Steph.Ability4.cost_CD = 40;
	
	Steph.Ability1.cost_HP = 0;
	Steph.Ability2.cost_HP = 0;
	Steph.Ability3.cost_HP = 0;
	Steph.Ability4.cost_HP = 0;

	Steph.Ability1.cost_MP = 10;
	Steph.Ability2.cost_MP = 20;
	Steph.Ability3.cost_MP = 30;
	Steph.Ability4.cost_MP = 40;

	Steph.Ability1.Ability_Level = 1;
	Steph.Ability2.Ability_Level = 2;
	Steph.Ability3.Ability_Level = 3;
	Steph.Ability4.Ability_Level = 4;

	Steph.Ability1.Ability_CallBack = &Abilities;
	Steph.Ability2.Ability_CallBack = &Abilities;
	Steph.Ability3.Ability_CallBack = &Abilities;
	Steph.Ability4.Ability_CallBack = &Abilities;
}

//Entry point
void DarkGDK(void)
{
	Player1.Character=Steph;
	Player1.TeamID = 1;

	dbPrint(dbStr(Player1.Character.Ability1.Ability_Level));

	dbWaitKey();
}

int Abilities(int ID, int Ability_Level)
{
	dbPrint(dbStr(ID));
	dbPrint(dbStr(Ability_Level));
	return 0;
}

however, I'm now getting the following compile error though:

Quote: ">.\Main.cpp(37) : error C2512: '_Player' : no appropriate default constructor available"

line 37 is simply "_Player Player1;"

BASIC programmers never die, they GOSUB and don't RETURN.

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JTK

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Joined: 10th Feb 2010

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Posted: 31st Jan 2011 02:12

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Personally, I like your second version better.

It's an easy fix. Change your "_Player" struct like so and all works fine:

+ Code Snippet

struct _Player
{
	int HP_Bonus, MP_Bonus, HP_Curr, MP_Curr;
	_Character Character;
	int x, y, TeamID;
};

The reason why is that instead of storing a reference to an already existing _Character (which requires a default assignment of *something* - hence the need for the default constructor), you are actually copying the data (the compiler builds that for you).

JTK

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Interplanetary Funk

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Joined: 19th Apr 2010

Location: Ipswich, United Kingdom

Posted: 31st Jan 2011 02:26

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Ah, I see, I forgot I left the reference in there, thanks very much, it seems to work fine now

BASIC programmers never die, they GOSUB and don't RETURN.

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