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+--- Thread: VC++ Game Class problem (/thread-7189.html)
VC++ Game Class problem - Martial_Law - Mar 29, 2003 05:10 PM
Hi everyone,
I am creating a chess game.
I have a game class that contains a game tree two players (can be human or computer)
what I am trying to do is:
In the constructor of for game, I want to call the constructor for PlayerA and PlayerB telling it if it is a human or computer player.
I am having problems with the constructor creating the players
Any help would be greatly appreciated
***Code Snippet***
Player Class //abstract class
{
....
public:
virtual bool Play(int Colour, GameTree* MyGameTree) = 0; //pure virtual function
}
Class Human : public Player //sub-class of player
{
.....
public:
bool Play(int Colour, GameTree* MyGameTree);
}
Class Computer : public Player //sub-class of player
{
.....
public:
bool Play(int Colour, GameTree* MyGameTree);
}
Class Game
{
private:
Player PlayerA
Player PlayerB
public:
Game::Game(); //default constructor
Game::Game(bool PlayerTypeA, bool PlayerTypeB); //constructor for creating
}
Game::Game(bool PlayerTypeA, bool PlayerTypeB)
{
.......
if (PlayerTypeA) //if human player
Player1 = Human(); //create human player
else
Player1 = Computer(); //create computer player
if (PlayerTypeB) //if human player
Player2 = Human(); //create human player
else
player2 = Computer(); //create computer player
.......
}
void Main(void)
{...
Game MyGame(true, false);
//create a game where playerA = human, playerB = computer
...
}
***end snippet***
is this how you would create two players inside a class or how would one do it?
I can get it to work if I do it like this:
Class Game
{
Human Player1;
Computer Player2;
}
void Main(void)
{
Game MyGame(true, false);
//create a game where playerA = human, playerB = computer
...
}
this will work, but I don't want to hard code whether the players are human or computer.
Thanks for any help
Martial Law
VC++ Game Class problem - Patrick - Mar 29, 2003 05:33 PM
be careful, this probably incorrect ( I think... ):
[sourcecode]
class A {
public:
virtual int f(int) = 0;
}
class B : public A {
public:
int f(int); // should be: "virtual int f(int);"
}
[/sourcecode]
declaring a pure virtual makes no sense if you then never add the virtual function to define it, heh.
And this wouldn't work right:
[sourcecode]
int main( void )
{
A* foobar = new B;
foobar->f(0);
}
[/sourcecode]
this should work:
[sourcecode]
// this is a bit better than passing bools, imo
typedef int PlayerType;
enum {
Human = 0,
Computer
};
class Player
{
...
public:
virtual bool Play( int Colour, GameTree* MyGameTree ) = 0;
};
class Human : public Player
{
...
public:
virtual bool Play( int Colour, GameTree* MyGameTree );
};
class Computer : public Player
{
...
public:
virtual bool Play( int Colour, GameTree* MyGameTree );
};
class Game
{
private:
Player* a;
Player* b;
public:
Game();
Game(PlayerType A, PlayerType B);
int Run( void );
};
Game::Game(PlayerType A, PlayerType B)
{
if( A == Human )
a = new Human;
else
a = new Computer;
if( B == Human )
a = new Human;
else
b = new Computer;
}
int Game::Run( void )
{
...
}
int main( void )
{
try {
Game* MyGame = new Game( Human, Computer );
}
catch (std::bad_alloc) {
return -1;
}
return MyGame->Run();
}
[/sourcecode]
VC++ Game Class problem - Mars_999 - Mar 29, 2003 07:21 PM
Actually you don't have to use the keyword virtual everytime you redefine the function after you declare the function virtual and that goes for pure virtual functions also. It's a matter of style I guess and their is nothing wrong with it. I myself use the keyword virtual on all my virtual functions to just to remind myself they are!!
VC++ Game Class problem - Patrick - Mar 29, 2003 07:47 PM
you're right. never seen that before, heh.
VC++ Game Class problem - Martial_Law - Mar 30, 2003 07:01 AM
Cheers guys
Yeah I declared the virtual function in human.cpp and computer.cpp sorry for the confusion.
Yeah I suppose I should call them virtual in human and computer classes,...
By changing the game declaration to
class Game
{
...
Player* A;
Player* B;
...
};
and passing in the enumerated data type "player type" it worked like a charm
I spent about 3 hours yesterday looking for any information about it...its a bit relief.
Thanks again,
Martial