maze.java

this is a maze with applet this code is in java :D

import java.awt.*;

public class Maze extends java.applet.Applet implements Runnable {

    int[][] maze;  // Description of state of maze.  The value of maze[i][j]
                   // is one of the constants wallCode, pathcode, emptyCode,
                   // or visitedCode.  (Value can also be negative, temporarily,
                   // inside createMaze().)
                   //    A maze is made up of walls and corridors.  maze[i][j]
                   // is either part of a wall or part of a corridor.  A cell
                   // cell that is part of a cooridor is represented by pathCode
                   // if it is part of the current path through the maze, by
                   // visitedCode if it has already been explored without finding
                   // a solution, and by emptyCode if it has not yet been explored.

    final static int backgroundCode = 0;
    final static int wallCode = 1;
    final static int pathCode = 2;
    final static int emptyCode = 3;
    final static int visitedCode = 4;
    
       // the next six items are set up in init(), and can be specified 
       // using applet parameters

    Color[] color = new Color[5];  // colors associated with the preceding 5 constants;
    int rows = 21;          // number of rows of cells in maze, including a wall around edges
    int columns = 21;       // number of columns of cells in maze, including a wall around edges
    int border = 0;         // minimum number of pixels between maze and edge of applet
    int sleepTime = 5000;   // wait time after solving one maze before making another
    int speedSleep = 50;    // short delay between steps in making and solving maze
    
    Thread mazeThread;   // thread for creating and solving maze
    Graphics me = null;  // graphics context for applet; created in checkSize()
    
    int width = -1;   // width of applet, to be set by checkSize()
    int height = -1;  // height of applet, to be set by checkSize()

    int totalWidth;   // width of applet, minus border area (set in checkSize())
    int totalHeight;  // height of applet, minus border area (set in checkSize())
    int left;         // left edge of maze, allowing for border (set in checkSize())
    int top;          // top edge of maze, allowing for border (set in checkSize())
    
    boolean mazeExists = false;  // set to true when maze[][] is valid; used in
                                 // redrawMaze(); set to true in createMaze(), and
                                 // reset to false in run()



    Integer getIntParam(String paramName) {
          // Utility routine for reading an applet param which is an integer.
          // Returns null if there is no such param, or if the value is not
          // a legal integer.
       String param = getParameter(paramName);
       if (param == null)
          return null;
       int i;
       try {
          i = Integer.parseInt(param);
       }
       catch (NumberFormatException e) {
          return null;
       }
       return new Integer(i);
    }
    
    Color getColorParam(String paramName) {
          // Utility routine for reading an applet param which is a color.
          // Returns null if there is no such param, or if the value is not
          // a legal color.  Colors can be specified as three integers,
          // separated by spaces, giving RGB components in the range 0 to 255;
          // the standard Java color names are also acceptable.
       String param = getParameter(paramName);
       if (param == null || param.length() == 0)
          return null;
       if (Character.isDigit(param.charAt(0))) {  // try to parse RGB color
          int r=0,g=0,b=0;
          int pos=0;
          int d=0;
          int len=param.length();
          while (pos < len && Character.isDigit(param.charAt(pos)) && r < 255) {
              d = Character.digit(param.charAt(pos),10);
              r = 10*r + d;
              pos++;
          }
          if (r > 255)
             return null;
          while (pos < len && !Character.isDigit(param.charAt(pos)))
             pos++;
          if (pos >= len)
             return null;
          while (pos < len && Character.isDigit(param.charAt(pos)) && g < 255) {
              d = Character.digit(param.charAt(pos),10);
              g = 10*g + d;
              pos++;
          }
          if (g > 255)
             return null;
          while (pos < len && !Character.isDigit(param.charAt(pos)))
             pos++;
          if (pos >= len)
             return null;
          while (pos < len && Character.isDigit(param.charAt(pos)) && b < 255) {
              d = Character.digit(param.charAt(pos),10);
              b = 10*b + d;
              pos++;
          }
          if (b > 255)
             return null;
          return new Color(r,g,b);          
       }
       if (param.equalsIgnoreCase("black"))
          return Color.black;
       if (param.equalsIgnoreCase("white"))
          return Color.white;
       if (param.equalsIgnoreCase("red"))
          return Color.red;
       if (param.equalsIgnoreCase("green"))
          return Color.green;
       if (param.equalsIgnoreCase("blue"))
          return Color.blue;
       if (param.equalsIgnoreCase("yellow"))
          return Color.yellow;
       if (param.equalsIgnoreCase("cyan"))
          return Color.cyan;
       if (param.equalsIgnoreCase("magenta"))
          return Color.magenta;
       if (param.equalsIgnoreCase("pink"))
          return Color.pink;
       if (param.equalsIgnoreCase("orange"))
          return Color.orange;
       if (param.equalsIgnoreCase("gray"))
          return Color.gray;
       if (param.equalsIgnoreCase("darkgray"))
          return Color.darkGray;
       if (param.equalsIgnoreCase("lightgray"))
          return Color.lightGray;
       return null;  // param is not a legal color
    }

    public void init() {
         Integer parm;
         parm = getIntParam("rows");
         if (parm != null && parm.intValue() > 4 && parm.intValue() <= 500) {
            rows = parm.intValue();
            if (rows % 2 == 0)
               rows++;
         }
         parm = getIntParam("columns");
         if (parm != null && parm.intValue() > 4 && parm.intValue() <= 500) {
            columns = parm.intValue();
            if (columns % 2 == 0)
               columns++;
         }
         parm = getIntParam("border");
         if (parm != null && parm.intValue() > 0 && parm.intValue() <= 100)
            border = parm.intValue();
         parm = getIntParam("sleepTime");
         if (parm != null && parm.intValue() > 0)
            sleepTime = parm.intValue();
         parm = getIntParam("speed");
         if (parm != null && parm.intValue() > 0 && parm.intValue() < 6)
            switch (parm.intValue()) {
               case 1: speedSleep = 1; break;
               case 2: speedSleep = 25; break;
               case 3: speedSleep = 50; break;
               case 4: speedSleep = 100; break;
               case 5: speedSleep = 200; break;
            }
         color[wallCode] = getColorParam("wallColor");
         if (color[wallCode] == null) 
            color[wallCode] = Color.black;
         color[pathCode] = getColorParam("pathColor");
         if (color[pathCode] == null)
            color[pathCode] = new Color(200,0,0);
         color[emptyCode] = getColorParam("emptyColor");
         if (color[emptyCode] == null)
            color[emptyCode] = new Color(128,128,255);
         color[backgroundCode] = getColorParam("borderColor");
         if (color[backgroundCode] == null)
            color[backgroundCode] = Color.white;
         color[visitedCode] = getColorParam("visitedColor");
         if (color[visitedCode] == null)
            color[visitedCode] = color[emptyCode];
         setBackground(color[backgroundCode]);
    }
    
    void checkSize() {
          // Called every time something is about to be drawn to
          // check the applet size and adjust variables that depend
          // on the size.  This includes a graphics context for the
          // applet.
       if (size().width != width || size().height != height) {
          width  = size().width;