Laboratory 6 Solutions

CSCI 132 Data Structures--Spring 2014

Laboratory 6 Solutions
Solution to board.cc code:
/*******************************************************************
 * Name: Brenda Student
 * Date: 3/19/14
 * Course: CSCI 132 Section 01
 * Assignment: Lab 6
 * Instructor: Royden
 * Program: board.cc
 * Purpose: Implementation of board class for playing game of eight
 ***************************************************************************/
#include "board.h"

Board :: Board() {
/*Post: Board is created and all variables initialized to zero */
  total = 0;
  moves_done = 0;
  last_move = 0;
}

int Board::evaluate( ) const {
/*Post: If player 1 wins, returns a value of 9 minus the number of moves taken,
  If player 2 wins, returns a value of -9 plus the number of moves taken. 
  If no winner yet, returns zero. */
  int winner = the_winner();
  if (winner == 1) {
    return 9 - moves_done;
  }
  else if (winner == 2) {
    return moves_done - 9;
  } else {
    return 0;
  }
}

bool Board::better(int value, int old_value) const {
/*Post: Returns true if value is better than old_value for the player who took the
	most recent move, returns false otherwise */
  if ((moves_done %2) == 1) {
    return (value < old_value);
  } else {
    return (value > old_value);
  }
}

int Board::worst_case( ) const {
/*Post: Returns the worst case value for the player who took the most recent move. */
  if ((moves_done%2) == 1) {
    return 9;
  } else {
    return -9;
  }
}


bool Board :: is_legal(int move) const {
/*Post: Returns true if proposed move is legal, false otherwise */
  if ((move < 1) || (move > 3) ) {
    return false;
  } else if (move == last_move) {
    return false;
  } else {
    return true;
  }
}

void Board::play(int move) {
/*Post: If move is legal, increments total by move, sets last_move to move and
	increments moves_done.  If move is not legal, it prints out an error message.*/
  if (is_legal(move)) {
    total += move;
    last_move = move;
    moves_done++;
  } else {
    cout << "Not a legal move! " << endl;
  }
}


int Board::the_winner() const {
/*Post: Returns 1 if player 1 has won, 2 if player 2 has won, and 0 if no winner yet */
  if (!done()) {
    return 0;
  } else if (total > 8) {
    return moves_done%2 + 1;
  } else {
    return 2 - moves_done%2;
  }
}

bool Board::done() const {
/*Post: Returns true if the game is over, false otherwise */
  if (total >= 8) {
    return true;
  } else {
    return false;
  }
}

int Board::getTotal( ) const {
/*Post: Returns total score so far. */
  return total;
}

void Board::instructions() {
/*Post: Prints out the instructions for the game. */
  cout << "Welcome to the game of eight!" << endl;
  cout << "In this game the players take turns choosing a number, 1, 2 or 3." 
       << endl;
  cout << "You may not choose the last number chosen. " << endl;
  cout << "A running total of the numbers is kept." << endl;
  cout << "If a player chooses a number to make the total equal to eight, " 
       << endl << "that player wins." << endl;
  cout << "If a player chooses a number to make the total greater than eight, "
       << endl << "that player loses." << endl << endl;
}