recursive function problems

[jomns]

Hi there,
I am writing a game called othello. This game is played by the computer and the computer user. The game is played on a board.
The player can choose between white and black color. Where blacks starts first. It's an assignment for college.

I have added the complete source code.
I am having problems with this recursive function:

int O_bord::eval(int diepte, int & i, int & j, bool spelersbeurt){
  
  int stand = 0; // voor de verschilfunctie
  int c, d; // variabelen voor de coordinaten en de for-lussen
  int voorlopigestand = 0; //om de waarde van een stand te retourneren
  int spelerzwart = -100; //warde voor speler met kleur zwart 
  int spelerwit = 100; //waarde voor speler met kleur wit
  
  //basis geval als diepte de waarde 0 bereikt
  if (diepte == 0 || speelcontrolle()){
     
     stand = verschil(); //de stand wordt geretourneerd
     
     return stand;      
  
  }//if
  
  //creert een nieuwe object O_bord om mee te werken
  O_bord b(hoogte, breedte, kleurspeler);
  b = *this;
  
    
  //cout << "De kopie wordt afgedrukt" << endl;
  //b.drukaf();//drukt af het nieuwe bord
   
  //als de diepte nog niet nul is
  for (c = 0; c < hoogte; c++){
    for(d = 0; d < breedte; d++){
      if (toegestanezet(c,d,spelersbeurt)){
        
	//cout << "Er werd een gezet op de nieuwe kopie" << endl;
	b = *this; //reset van het nieuwe bord
	
	b.doezet(c,d,spelersbeurt); // een zet wordt uitgevoerd op de nieuwe object
	
	//b.drukaf(); ////drukt af het nieuwe bord
	
	//b.spelersbeurt = !spelersbeurt; // beurten worden geswicht
	spelersbeurt = true; // beurten worden geswicht
	
	
	voorlopigestand = b.eval((diepte -1), i, j, spelersbeurt); //hier wordt dieper gekeken
	
	//enkele statistieken
	cout << "diepte: " << diepte << " c: " << c << " d: " << d << " i: " << i << 
	     " j: " << j <<" voorlopigestand: " << voorlopigestand << endl;
	
	spelersbeurt = false; //beurten worden geswicht
	
	//================================//
	//als de computer met zwart speelt//
	//================================//
	if (computersgetal == 1){ 
	  
	  //als de computer aan de beurt is
	  if(!spelersbeurt){
	  
	    //de voorlopige beste zet wordt opgeslagen
	    if (voorlopigestand >= spelerwit){
	      i = c; 
	      j = d;
	      spelerwit = voorlopigestand;
	    }//if
	    
	  }//if
	  
	  //als de computer niet aan de beurt is
          else {
	  
	    if (voorlopigestand <= spelerzwart) {
	      i = c; 
	      j = d;
	      spelerzwart = voorlopigestand;
	    }//if
	    
	  }//else  
	
	}//if
	
	//==============================//
	//als de computer met wit speelt//
	//==============================//
	if (computersgetal == 2){
	  
	  //als de computer aan de beurt is
	  if (!spelersbeurt){
	    
	    if (voorlopigestand <= spelerzwart){
	      i = c; 
	      j = d;
	      spelerzwart = voorlopigestand;
	    }//if
	    
	  }//if
	  
	  //als de computer niet aan de beurt is
	  else {
	    
	    if (voorlopigestand >= spelerwit){
	      i = c; 
	      j = d;
	      spelerwit = voorlopigestand;
	    }//if
	  
	  }//else
	}//if
         
      }//if
    }//for
  }//for
	
  
  //geef aan welke waarden geretourneerd moeten worden
  if (computersgetal == 1){
    return spelerzwart;
  }
  else {
    return spelerwit;
  }

}//othello::eval



void O_bord::verstandigezet(bool spelersbeurt, int diepte){
  
  int x; // wordt toegekend aan de functieaanroep eval
  int i,j; //coordinaten voor de functie  
  // de recursieve functie moet dan de bestezet bepalen
  x = eval (diepte, i, j, spelersbeurt);
	 
  cout << "i: " << i << "j: " << j << " binnen verstandigezet " << endl;
  // voert uit de verstandigezet voor de computer
  
  //checkt eerst of de coordinaten correct zijn zodat de variabelen van die zet true worden in toegestanezet
  if (toegestanezet(i,j,spelersbeurt)) {
    doezet(i, j, spelersbeurt); 
  }//if     
}//O_bord::verstandigezet

Some way I don't get the right coordinates passed to doezet(i,j, spelersbeurt)

So if anyone can give me some comments. I'll appreciate it.
If you don't understand, because of the comments
written in dutch, let me now.

Thanks

[alphaoide]

I think we should make English as the standard for variable/function naming. This is just like reading an assembly language

[killgore]

What doesn't work (versta je code wel), works all fine in here (didn't notice a thing).

Maybe you swapped height and width

[jomns]

To Killgore.

The problem we have now is that when we try the option verstandig zetten and diepte e.g 2, so the computer sees the status of the game two turns ahead and decides what the best i and j coordinates are to make a move. But the function eval() doens't pass the correct coordinates i and j to the doezet function in verstandigezet().

when you try the option verstandig and diepte 2 you will see that the computer doesn't make a move at all.

Can you please take a look a it.

thanks

Jonathan

[tu_user]

I agree with alphaoide.

[jomns]

Hi there,
this is the english version of my recursive function:

//=======================================================================================//
//                      function which finds the best computer's move  		         //
//=======================================================================================//
int O_board::eval(int depth, int & i, int & j, bool playersturn){
  
  int score = 0; // for the difference() fucntion
  int c, d; // variables needed for the for-loops
  int tempscore = 0; //to store the value of the temporary score 
  int playerblack = -100; //value for the player with black color 
  int playerwhite = 100; //value for the player with white color
  
  //basic case if depth reaches value zero
  if (depth == 0 || gamecontrol()){
     
     score = difference(); //returns the score
     
     return score;      
  
  }//if
  
  //creates a new object O_board to work with
  O_board b(height, width, playerscolor);
  b = *this;
  
    
  //cout << "The copy is printed" << endl;
  //b.print();//prints the new board
   
  //if depth hasn't reached value zero
  for (c = 0; c < height; c++){
    for(d = 0; d < width; d++){
      if (move_permitted(c,d, playersturn)){
        
	//cout << "A move was made on the board" << endl;
	b = *this; //resets the new board 
	
	b.executemove(c,d,playersturn); // a move is executed on the new board
	
	//b.print(); ////prints the new board	
	
	playersturn = true; // turns are switched between computer and player
	
	
	tempscore = b.eval((depth -1), i, j, playersturn); //The computer looks further more moves
	
	//some statistics
	cout << "depth: " << depth << " c: " << c << " d: " << d << " i: " << i << 
	     " j: " << j <<" tempscore: " << tempscore << endl;
	
	playersturn = false; // turns are switched between player and computer
	
	//================================//
	//if the computer plays with black//
	//================================//
	if (computersnumber == 1){ 
	  
	  //if it's the computer's turn
	  if(!playersturn){
	  
	    //stores the temporary best score
	    if (tempscore >= playerwhite){
	      i = c; 
	      j = d;
	      playerwhite = tempscore;
	    }//if
	    
	  }//if
	  
	  //if it's not the computer's turn
          else {
	  
	    if (tempscore <= playerblack) {
	      i = c; 
	      j = d;
	      playerblack = tempscore;
	    }//if
	    
	  }//else  
	
	}//if
	
	//==============================//
	//if the computer plays with white//
	//==============================//
	if (computersnumber == 2){
	  
	  //if it's computer's turn
	  if (!playersturn){
	    
	    if (tempscore <= playerblack){
	      i = c; 
	      j = d;
	      playerblack = tempscore;
	    }//if
	    
	  }//if
	  
	  //if it's not the computer's turn
	  else {
	    
	    if (tempscore >= playerwhite){
	      i = c; 
	      j = d;
	      playerwhite = tempscore;
	    }//if
	  
	  }//else
	}//if
         
      }//if
    }//for
  }//for
	
  
  //decides which value should be returned
  if (computersnumber == 1){
    return playerblack;
  }
  else {
    return playerwhite;
  }

}//othello::eval


//=======================================================================================//
//                      function which executes a smart move on board    	         //
//=======================================================================================//
void O_board::smart_move(bool playersturn, int depth){
  
  int x; // stores the value returned by eval
  int i,j; //coordinates for the fucntion eval  
  
  // calling of the recursive fucntion which determined the best move for the computer
  x = eval (depth, i, j, playersturn);
	 
  cout << "i: " << i << "j: " << j << " inside smart_move " << endl;
  
  //checks first if the coordinates a permitted move are
  // then exexutes the move on the real board
  if (move_permitted(i,j,playersturn)) {
    executemove(i, j, playersturn); 
  }//if     
}//O_bord::smart_move

The problem we have now is that when we try the option smart_move and depth e.g 2, so the computer sees the status of the game two turns ahead and decides what the best i and j coordinates are to make a move. But the function eval() doens't pass the correct coordinates i and j to the executemove() function in smart_move().

when you try the option verstandig and diepte 2 you will see that the computer doesn't make a move at all.

Can you please take a look a it.

thanks

Jonathan

[alphaoide]

I don't know, dude. A combination of recursive function and loops blows my head. Do you know how to debug? Trace the value of i and j and find where they return the incorrect values.