World Image Recursion Exercise

Make this picture using recursion, building one block at a time, for as many blocks as requested. Use recursion.

Start with this program, and fill in the recursive method:

import javalib.worldimages.*;

import java.awt.Color;

import java.util.Scanner;

import javalib.worldcanvas.*;

public class Checkerboard

{

public static void main(){

Scanner screen = new Scanner(System.in);

WorldCanvas canvas = new WorldCanvas(1000,1000);

canvas.show();

int numberSquares;

do{

System.out.println("Enter the number of squares");

numberSquares = screen.nextInt();

WorldImage cBoard= makeCheckerBoardRow(numberSquares) ;

canvas.clear();

canvas.drawImage(cBoard);

}while(numberSquares > 0);

canvas.close();

}

/**

* Make a checkboard Row image of the size given

* questions to ask yourself:

* When will I want to return nothing or one square?

* When I am asked for 3 squares what will I have available to me?

* Remember you have the parameter variables

* and the result of any other possible call to makeCheckerBoardRow

*/

public static WorldImage makeCheckerBoardRow(int size){

if (size <= 1){

return AImage.makeRectangle(50,50,Color.RED,Mode.FILLED);

}

else if (size % 2 == 0){

return makeCheckerBoardRow(size - 1).beside(AImage.makeRectangle(50,50,Color.BLACK,Mode.FILLED));

}

else

{

return makeCheckerBoardRow(size - 1).beside(AImage.makeRectangle(50,50,Color.RED,Mode.FILLED));

}

}

}

Notes on PictureIT:

Import the following libraries:

· import javalib.worldimages.*;

· import javalib.worldcanvas.*;

· import java.awt.Color;

Methods you will need:

makeRectangle Static method of AImage:

· makeRectangle(int width, int height, Color color, Mode mode) will return a rectangle. The available Modes are FILLED (aka SOLID) and OUTLINED. You can use colors: BLACK, RED, BLUE and others.

· Example: WorldImage mypic = AImage.makeRectangle(50,50,Color.RED,Mode.FILLED);

beside Instance method of WorldImage:

· beside(WorldImage

... others) Returns a WorldImage that  Concatenates two or more images horizontally.

· Example: WorldImage twoSquares = AImage.makeRectangle(50,50,Color.RED,Mode.FILLED).beside(AImage.makeRectangle(50,50,Color.BLACK,Mode.FILLED));

· Example2: WorldImage pic = pic1.beside(pic);

show Instance method of WorldCanvas:

· show() : Show an empty window.

· Example: mycanvas.show();

drawImage Instance method of WorldCanvas:

· drawImage(WorldImage) places the image on the canvas starting at 0,0.

· Example: mycanvas.drawImage(mypic);

clear Instance method of WorldCanvas:

· clear() removes the picture currently on the canvas.

· Example: mycanvas.clear();

close Instance method of WorldCanvas:

· close() closes the canvas window

· Example: mycanvas.close();

Find all picture it library javadoc at:

· http://home.adelphi.edu/sbloch/javalib_doc/

· Click on AImage for all methods to create shapes.

· Click on WorldImage for all methods to place shapes or adjust them.

· Click on WorldCanvas for the methods to control the window