Add second year

second/semester2/CT255/Assignments/Assigment-04/Alien.java

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+import java.awt.*;
+import javax.swing.*;
+
+public class Alien extends Sprite2D {
+    private int stepSize = 2;
+
+    public Alien(Image image) {
+        super(image);
+    }
+
+    // method to randomly move the alien
+    public void move(boolean right) {
+        // changing the x & y co-ordinates (inherited from superclass) by either plus or minus the stepSize, depending on the direction
+        if (right) {
+            x += stepSize;
+        }
+        else {
+            x -= stepSize;
+        }
+    } 
+
+    // method to move aliend down 
+    public void moveDown() {
+        y += 10;
+    }
+
+    // getter method for the alien's x coordinate 
+    public int getx() {
+        return x; 
+    }
+}

second/semester2/CT255/Assignments/Assigment-04/InvadersApplication.java

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+import java.awt.*;
+import java.awt.event.*;
+import javax.swing.*;
+import java.awt.image.*;
+
+public class InvadersApplication extends JFrame implements Runnable, KeyListener {
+    // member data
+    private static String workingDirectory = System.getProperty("user.dir");
+    
+    private Image alienImage;
+    private Image playerImage;
+
+    private static final Dimension WindowSize = new Dimension(800, 600); 
+    private static final int NUMALIENS = 30; 
+    private Alien[] AliensArray = new Alien[NUMALIENS]; 
+    boolean right = true;   // boolean to tell which direction the aliens are moving
+    private Player player;
+
+    private BufferStrategy strategy; 
+
+    // variable to hold how far the player should be moving in the x axis per frame - default 0. 
+    private int dx = 0; 
+
+    // constructor 
+    public InvadersApplication() {
+        // set up window
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
+
+        // adding a key listener
+        addKeyListener(this);
+
+        // display the window. centred on the screen
+        Dimension screensize = java.awt.Toolkit.getDefaultToolkit().getScreenSize(); 
+        int x = screensize.width/2  - WindowSize.width/2; int y = screensize.height/2 - WindowSize.height/2;
+        setBounds(x, y, WindowSize.width, WindowSize.height);
+
+        // load image from disk 
+        ImageIcon alienIcon = new ImageIcon(workingDirectory + "/alien_ship_1.png");
+        ImageIcon playerIcon = new ImageIcon(workingDirectory + "/player_ship.png");
+
+        alienImage = alienIcon.getImage();
+        playerImage = playerIcon.getImage();
+        
+        // initial x and y coordinates for the aliens
+        int alienx = 200; 
+        int alieny = 25;
+        int column = 0;     // keeps track of which column the alien is in 
+        for (int i = 0; i < NUMALIENS; i++) {
+            AliensArray[i] = new Alien(alienImage);
+            AliensArray[i].setPosition(alienx, alieny);
+
+            alienx += 60;
+            column++;
+
+            // go onto a new line every 5 aliens
+            if (column >= 6) {
+                column = 0;
+                alienx = 200; 
+                alieny += 60;
+            }
+        }
+
+        // creating a player icon & setting it's position 
+        player = new Player(playerImage);
+        player.setPosition(270, 550);
+
+        setVisible(true);
+
+        createBufferStrategy(2); 
+        strategy = getBufferStrategy(); 
+
+        // create a new thread & start it 
+        Thread t = new Thread(this);
+        t.start();
+    }
+
+    // thread's entry point
+    public void run() {
+        while (true) {
+            // repainting 
+            this.repaint();
+
+            try {
+                Thread.sleep(20); 
+            } catch (InterruptedException e) {
+                e.printStackTrace(); 
+            } 
+        }
+    }
+
+    @Override
+    public void keyPressed(KeyEvent e) {
+        // getting the keycode of the event 
+        int key = e.getKeyCode();
+
+        // if right key pressed, making the distance to be moved 10px to the right 
+        if (key == KeyEvent.VK_RIGHT) {
+            dx = 5;
+        }
+        // if left key pressed, making the distance to be moved 10px to the left
+        if (key == KeyEvent.VK_LEFT) {
+            dx = -5;
+        }
+    }
+
+    @Override
+    public void keyReleased(KeyEvent e) {
+        // getting the keycode of the event 
+        int key = e.getKeyCode();
+
+        // if the key released was the left or right arrow, setting dx back to 0
+        if (key == KeyEvent.VK_RIGHT || key == KeyEvent.VK_LEFT) {
+            dx = 0;
+        }
+    }
+
+    @Override 
+    public void keyTyped(KeyEvent e) {
+    }
+
+    // application's paint method
+    public void paint(Graphics g) {
+        g = strategy.getDrawGraphics(); 
+        // draw a black rectangle on the whole canvas 
+        g.setColor(Color.BLACK); 
+        g.fillRect(0, 0, 800, 600);
+
+
+        // iterating through each sprite, moving it, and calling it's paint method 
+        for (Alien a : AliensArray) {
+            a.move(right);
+            a.paint(g);
+        }
+
+        // checking if any of the aliens hit the edge when they were moved 
+        for (Alien a : AliensArray) {
+            // changing direction & moving down if edge is hit 
+            if (a.getx() > 750) {
+                right = false; 
+
+                // looping through all the aliens and moving them down
+                for (Alien alien : AliensArray) {
+                    alien.moveDown(); 
+                }
+
+                break;
+            }
+            else if (a.getx() < 0) {
+                right = true;
+
+                // looping through all the aliens and moving them down
+                for (Alien alien : AliensArray) {
+                    alien.moveDown(); 
+                }
+
+                break;
+            }
+        }
+
+        // moving the player dx pixels - should be 0 if no key is being pressed 
+        player.move(dx); 
+
+        // calling the Player's paint method 
+        player.paint(g);
+
+        strategy.show();
+    }
+
+    // application entry point 
+    public static void main(String[] args) {
+        InvadersApplication ia = new InvadersApplication(); 
+    }
+}

second/semester2/CT255/Assignments/Assigment-04/Player.java

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+import java.awt.*;
+import javax.swing.*;
+
+public class Player extends Sprite2D {
+    public Player(Image image) {
+        super(image);
+    }
+
+    // method to move the player by the supplied distance
+    public void move(int distance) {
+        x += distance; // x is inherited from the Sprite2D superclass
+    }
+}

second/semester2/CT255/Assignments/Assigment-04/Sprite2D.java

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+import java.awt.*;
+import javax.swing.*;
+
+public class Sprite2D {
+    // member data
+    protected int x,y;
+    private Image image;
+
+    public Sprite2D(Image image) {
+        this.image = image;
+    }
+
+    // paint method
+    public void paint(Graphics g) {
+        // draw the image 
+        g.drawImage(image, x, y, null);
+    }
+
+    // set the position of the object
+    public void setPosition(int x, int y) {
+        this.x = x; 
+        this.y = y; }
+}