/**
 * Test how to generate and display a two-dimensional random array.
 * For classroom demonstration.
 * 
 *
 * @author Xiannong Meng
 *
 * August 2006
 */
import java.io.*;
import java.util.*;

class TestRandomArray {

  /*
   * Some useful constants
   */
  private static final double MAX_PCNT_LIV = 0.8;  // upper limit
  private static final double MIN_PCNT_LIV = 0.2;  // lower limit

  /*
   * The array
   */
  private boolean [][] mBoard;   // Good for a two-dimensional world
  private int mDimension;        // the size of the board


  /**
   * Constructor that initializes the two dimensional array
   *
   * @param dimension: an integer specifying the dimension of the array
   * @param probLife: initial probability of life in a cell
   */
  public TestRandomArray(int dimension, double probLife) {

    mDimension = dimension;
    mBoard = new boolean[mDimension][mDimension];
    for (int i = 0; i < mBoard.length; i++)
      for (int j = 0; j < mBoard[i].length; j++)
	mBoard[i][j] = (Math.random() < probLife);
  }

  /**
   * display prints the board in text form on the screen
   */
  public void display() {

    for (int i = 0; i < mBoard.length; i++) {
      for (int j = 0; j < mBoard[i].length; j++)
	if (mBoard[i][j] == true)
	  System.out.print("+");
	else
	  System.out.print("-");
      System.out.println();
    }
  }

  /**
   * A simple, minimum test program to see if the 2-D random array works.
   */
  public static void main(String[] argv) {

    TestRandomArray runATest = new TestRandomArray(8, 0.4);
    runATest.display();
  }
}