package cse1030;

public class GameScore {
  private static GameScore INSTANCE = new GameScore();
  
  private int score;
  
  private GameScore() {
    this.score = 0;
  }
  
  /**
   * Get the single instance of the game score manager.
   * 
   * @return The single instance of the game score manager.
   */
  public static GameScore getInstance() {
    return GameScore.INSTANCE;
  }
  
  /**
   * Get the score.
   * 
   * @return The score.
   */
  public int getScore() {
    return this.score;
  }
  
  /**
   * Increase the score by a specified amount.
   * 
   * @param inc The amount to increase the score by.
   * @pre. <code>inc >= 0</code>
   */
  public void increase(int inc) {
    this.score += inc;
  }
  
  /**
   * Decrease the score by a specified amount.
   * 
   * @param dec The amount to decrease the score by.
   * @pre. <code>dec >= 0</code>
   */
  public void decrease(int dec) {
    this.score -= dec;
  }
  
  public static void main(String[] args) {
    GameScore s = GameScore.getInstance();
    s.increase(5);
    System.out.println(s.getScore());
    
    GameScore t = GameScore.getInstance();
    t.increase(5);
    System.out.println(s.getScore());
  }
}