Code

/*
 * Author: Emily Wang
 * Date: March 24, 2016
 * Assignment: Snow Plow
 * Due Date :March 30, 2016
 * Description: gui version
 */

//IMPORT NEEDED PACKAGES//
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class SnowPlow extends JFrame implements ActionListener {
  
  //static variables declaration//
  static int column = 0;
  static int r = 5, c = 5;
  static int time = 0;
  static Timer timer;
  static JLabel used;
  
  
  //2D arrays declaration//
  JLabel num[][];
  int grid[][];
  
  
  // ADD PANELS//
  static JPanel Intro = new JPanel(); // intro panel
  static JPanel button = new JPanel(); // button panel
  static JPanel Grid = new JPanel(); // grid panel
  static JPanel instruction = new JPanel();
  
  
  // ADD COMPONENTS//
  JLabel name = new JLabel("Please enter your name: ");
  JTextField N = new JTextField("name", 15); // label and textfield for name
  JLabel R = new JLabel("Row: ");
  JTextField row = new JTextField("5", 5);
  JLabel C = new JLabel("Column: ");
  JTextField col = new JTextField("5", 5); // label and textfield for row and column
  JButton enter = new JButton("generate grid"); // button
  JButton plow = new JButton("Plow");
  JButton restart = new JButton("Regenerate Grid");
  JButton rule = new JButton("How To Use");
  JButton back = new JButton("back");
  JButton menu = new JButton("Back to menu");
  
  
  // static layouts//
  static GridLayout Whole;
  static BoxLayout ins;
  static GridLayout in;
  static GridLayout p;
  
  
  // constructor//
  public SnowPlow() {
    setTitle("Snow Plow Program");
    setSize(700, 700); // set title and size of program
    
    
    used = new JLabel(" ", JLabel.CENTER);
    
    
    // action listeners//
    enter.addActionListener(this);
    plow.addActionListener(this);
    restart.addActionListener(this);
    rule.addActionListener(this);
    back.addActionListener(this);
    menu.addActionListener(this);
    
    
    // layouts//
    Whole = new GridLayout(4, 2);
    in = new GridLayout(6, 1);
    ins = new BoxLayout(Intro, BoxLayout.Y_AXIS);
    p = new GridLayout(5, 1);
    
    
    setLayout(new BorderLayout()); // set entire frame to borderlayout
    
    // add components to intro panel/
    Intro.setLayout(Whole);
    Intro.add(name);
    Intro.add(N);
    Intro.add(R);
    Intro.add(row);
    Intro.add(C);
    Intro.add(col);
    Intro.add(enter);
    Intro.add(rule);
    
    
    add(Intro, BorderLayout.CENTER); // add intro panel
    setVisible(true);
  }
  
  //ACTION LISTENERS- BUTTONS//
  public void actionPerformed(ActionEvent event) {
    String command = event.getActionCommand();
    
    
    // if user presses how to use button//
    if (command.equals("How To Use")) {
      Intro.removeAll();
      Intro.setLayout(in);
      
      //set 5 labels to 5 lines of instruction//
      Font labels = new Font("Avenir", Font.PLAIN, 20);
      JLabel use1 = new JLabel("- enter the number of rows and columns you want the grid to be ", JLabel.CENTER);
      JLabel use2 = new JLabel("- click generate grid to see the randomly generated grid ", JLabel.CENTER);
      JLabel use3 = new JLabel("- after seeing the grid, click plow to change touching 1s to 0s", JLabel.CENTER);
      JLabel use4 = new JLabel("- if you want to regenerate a grid, click regenerate grid", JLabel.CENTER);
      JLabel use5 = new JLabel("- after clicking regenerate grid, click plow execute program again", JLabel.CENTER);
      
      //set the font of all 5 labels//
      use1.setFont(labels);
      use2.setFont(labels);
      use3.setFont(labels);
      use4.setFont(labels);
      use5.setFont(labels);
      
      //add the 5 labels onto intro panel//
      Intro.add(use1);
      Intro.add(use2);
      Intro.add(use3);
      Intro.add(use4);
      Intro.add(use5);
      Intro.add(back); // adding all rules onto instruction panel
      
      add(Intro);
      clear();
    }
    
    
    //if user presses back on the instruction page or back to menu on the grid page//
    if (command.equals("back") || command.equals("Back to menu")) {
      //remove everything on intro panel//
      Intro.removeAll();
      
      //remove grid if it is there//
      remove(Grid);
      
      //add all the components on the original intro panel back//
      Intro.setLayout(Whole);
      Intro.add(name);
      Intro.add(N);
      Intro.add(R);
      Intro.add(row);
      Intro.add(C);
      Intro.add(col);
      Intro.add(enter);
      Intro.add(rule);
      add(Intro, BorderLayout.CENTER);
      clear();
    } // add all components back onto intro panel
    
    
    //if user presses generate grid on the intro panel//
    if (command.equals("generate grid")) {
      // get the user's name from textfield//
      String n = N.getText();
      
      Grid.removeAll();
      //remove all components on the intro panel/
      Intro.removeAll();
      
      //output a greeting on a label//
      JLabel NAME = new JLabel("Hello " + n + ", Welcome to the snow plow program!", JLabel.CENTER);
      NAME.setFont(new Font("Avenir", Font.PLAIN, 30));
      
      //add components onto the intro panel//
      Intro.setLayout(p);
      Intro.add(NAME); // clear the intro panel and output user greeting
      Intro.add(plow);
      Intro.add(restart);
      Intro.add(menu);
      Intro.add(used);
      
      //get the row and column numbers user entered from textfields//
      String a, b;
      a = row.getText();
      b = col.getText(); // get the string value from the two textfields
      r = Integer.parseInt(a);
      c = Integer.parseInt(b); // convert them to integer values
      
      //set layout of the grid//
      GridLayout label_display = new GridLayout(r, c);
      Grid.setLayout(label_display);
      
      //declare the 2D array numbers and labels//
      grid = new int[r][c]; // declare the 2D number array with the size user inputed
      num = new JLabel[r][c]; // declare 2D label array with the same size as the number array
      
      //call initialize method to initialize all labels to empty space//
      initialize(r, c);
      
      // call generate method to store random values into the array//
      generate(grid, r, c); 
      
      // call method assign to assign the values from the number array grid into this label//
      assign(grid, r, c); 
      
      //add panels//
      add(Intro, BorderLayout.NORTH);
      add(Grid, BorderLayout.CENTER);
      
      clear();
    }
    
    
    //if the user presses plow button, use recursion to perform task//
    if (command.equals("Plow")) {
      time = 0;
      int exist = check(grid, r, c); // call method check and store the returned value into variable exist
      Intro.setLayout(p);
      int r_change = 0; // row value of first one if found
      
      if (exist == -1) {
        used.setText("Snow plow not used"); // if 1 does not exist, set a label to snow plow not used
      } 
      else {
        used.setText(" ");
        change(grid, r_change, exist); // call method to make changes to the grid
      }
      clear();
    }
    
    
    //if user presses regenerate grid on the grid page//
    if (command.equals("Regenerate Grid")) {
      //remove existing grid//
      Grid.removeAll();
      
      used.setText(" ");
      
      generate(grid, r, c); // call generate method to store random values into the array
      assign(grid, r, c); // call method assign to assign the values from the number array grid into this label
      clear();
      
    }
  }
  
  
  //initialize method to initialize JLabels//
  public void initialize(int r, int c) {
    for (int i = 0; i < r; i++) {
      for (int j = 0; j < c; j++)
        num[i][j] = new JLabel(" ");   //set all JLabels to a space
    }
  }
  
  
  //generate method used to generate random numbers to number array//
  public static void generate(int[][] a, int r, int c) {
    for (int i = 0; i < r; i++) {
      for (int j = 0; j < c; j++)
        a[i][j] = (int) (Math.random() * 2 + 1); // assign 1s and 2s randomly to the 2D number array
    }
  }
  
  
  //assign method used to add all numbers on number array onto JLabel array and display them on grid//
  public void assign(int b[][], int r, int c) {
    
    for (int i = 0; i < r; i++) {
      for (int j = 0; j < c; j++) {
        num[i][j].setText(" " + String.valueOf(b[i][j])); //set text in each element of JLabel to the value in the array
        
        num[i][j].setFont(new Font("Times New Roman", Font.BOLD, 30));   //set the font
        if (b[i][j] == 1) {
          num[i][j].setForeground(new Color(135, 206, 250));  //set different colors to 1, 2, and 0
          num[i][j].setBackground(new Color(255, 255, 204));
          num[i][j].setOpaque(true);
        } else if (b[i][j] == 2) {
          num[i][j].setForeground(new Color(255, 204, 255));
          num[i][j].setBackground(new Color(204, 255, 229));
          num[i][j].setOpaque(true);
        } 
        Grid.add(num[i][j]); // add all labels onto panel Grid
      }
    }
  }
  
  
  //check method used to check if there is 1 in the first row and return position of 1//
  public int check(int a[][], int r, int c) {
    int one = -1; // initialize variable one to -1
    
    for (int i = 0; i < c; i++) {
      if (a[0][i] == 1) {
        one = i; // if there is 1 in first row, store the value of column into one and break the loop
        break;   
      }
    }
    return one; // return the value in one
  }
  
  
  //actual recursion method to perform the task//
  public void change(int[][] a, int R, int C) {
    
    int r = a.length;
    int c = a[0].length;
    column = a[0].length;
    
    if (a[R][C] == 1) { // if the number at R,C is 1, change to 0 and call recursive methods
      a[R][C] = 0;
      
      delay(a,R,C); //call delay method and pass the array, row, and col values into it to delay display
      
      if (R > 0 && C > 0)
        change(a, R - 1, C - 1); // move down and left if row and col are both greater than 0
      if (C < c - 1)
        change(a, R, C + 1); // move right one if it is less than number of col-1
      if (C > 0)
        change(a, R, C - 1); // move left one if point c>0
      if (R < r - 1 && C < c - 1)
        change(a, R + 1, C + 1); // move up and right it it does not go past boundary
      if (R > 0 && C < c - 1)
        change(a, R - 1, C + 1); // move down and right
      if (R < r - 1)
        change(a, R + 1, C); // move up
      if (R > 0)
        change(a, R - 1, C); // move down
      if (R < r - 1 && C > 0)
        change(a, R + 1, C - 1); // move up and left
      // ALL 8 POSSIBILITIES IN RECURSION//
    }
  }
  
  public void clear() {
    validate();
    repaint();   //validate and repaint after remove all and adding new components
  }
  
  //delay method//
  public void delay (final int [][]a, final int r, final int c){//change 1s to 0s one by one with swing timer
    timer = new Timer(time++ * 300, new ActionListener(){
      public void actionPerformed (ActionEvent e){
        ((JLabel) Grid.getComponent(r*column + c)).setText("0"); 
        ((JLabel) Grid.getComponent(r*column + c)).setBackground(new Color(229, 204, 255));
        ((JLabel) Grid.getComponent(r*column + c)).setForeground(new Color(153, 255, 255));
        ((JLabel) Grid.getComponent(r*column + c)).setOpaque(true);
        //get the component of the label 1, change to 0 and change color of text and background//
      } 
    });
    timer.setRepeats(false); // ensures timer does not repeat 
    timer.start(); // starts the timer 
  } 
  
  
  public static void main(String args[]) {
    new SnowPlow(); // adding frame to main
  }
}