P 6.3) import java.util.scanner;

Transcription

1 P 6.3) import java.util.scanner; public class CurrencyConverter public static void main (String[] args) Scanner in = new Scanner(System.in); System.out.print("How many euros is one dollar: "); double rate = in.nextdouble(); boolean done = false; while (!done) System.out.print("Dollar value (Q to quit): "); String input = in.next(); if (input.equalsignorecase("q")) done = true; else double amount = Double.parseDouble(input); double exchange = amount * rate; System.out.printf("%.2f dollar = %.2f euro\n", amount, exchange); //System.out.println(amount + " dollor = " + exchange + " euro"); P 6.4) below you can find the tester class for this question. The main cannonball class is really easy to implement. So you need to do that your self. public static void main(string[] args) Scanner in = new Scanner(System.in); System.out.print("Enter the initial velocity: "); double ivel = in.nextdouble(); final double G = 9.81; double deltat = 0.01; double t = 0; double exactpos = 0; int steps = 0; Cannonball cb = new Cannonball(ivel); do cb.move(deltat); t = t + deltat; steps++; exactpos = -0.5 * G * t * t + ivel * t;

2 if (steps % 100 == 0) System.out.println("Simulation position: " + cb.getposition() + " Velocity: " + cb.getvelocity()); System.out.println("The exact formula position is: " + exactpos); while (exactpos > 0); P 6.5) This question is really easy and just for a hint you can use the constructor below: public PowerGenerator(int afactor) currentpower = 1; factor = afactor; P 6.11) public double nextguess() xold = xnew; if (count == 0) // first time xnew = 1; else xnew = xold * (1-1.0 / n) + a / (n * Math.pow(xOld, n - 1)); count++; return xnew;. public boolean hasmoreguesses() return count <= 2 Math.abs(xNew - xold) > epsilon; P 6.15) this question requires 4 classes. The full solution came below. /** This class tests the Drunkard and Grid classes. */ public class DrunkardViewer public static void main(string[] args) JFrame frame = new JFrame(); frame.setsize(270, 300); frame.settitle("drunkardviewer");

3 frame.setdefaultcloseoperation(jframe.exit_on_close); DrunkardComponent component = new DrunkardComponent(); frame.add(component); frame.setvisible(true);.. public class Grid private static final int RADIUS = 3; private int size; private int nsquares; public Grid(int asize, int ansquares) size = asize; nsquares = ansquares; public void draw(graphics2d g2) // draw the x-direction of the grid double x; for (x = 0; x <= nsquares; x++) Line2D.Double l = new Line2D.Double(x * size, 0, x * size, nsquares * size); g2.draw(l); // draw the y-direction of the grid double y; for (y = 0; y <= nsquares; y++) Line2D.Double l = new Line2D.Double(0, y * size, nsquares * size, y * size); g2.draw(l); public class DrunkardComponent extends JComponent public void paintcomponent(graphics g) Graphics2D g2 = (Graphics2D) g; final int NSQUARES = 20; final int RADIUS = 3;

4 final int MAX_MOVES = 100; int size = Math.min(getWidth(), getheight()) / NSQUARES; Grid mygrid = new Grid(size, NSQUARES); mygrid.draw(g2); int x = NSQUARES / 2; int y = NSQUARES / 2; Drunkard d = new Drunkard(x, y); for (int i = 1; i <= MAX_MOVES; i++) d.move(); x = d.getrow(); y = d.getcolumn(); Ellipse2D.Double e = new Ellipse2D.Double(x * size - RADIUS, y * size - RADIUS, 2 * RADIUS, 2 * RADIUS); g2.draw(e);. /** This class provides methods to simulate the movement of a drunkard. */ public class Drunkard private static final int UP = 0; private static final int DOWN = 1; private static final int LEFT = 2; private static final int RIGHT = 3; private int x; private int y; private Random generator; public Drunkard(int anx, int ay) x = anx; y = ay; generator = new Random(); public void move() int move = generator.nextint(4); if (move == UP) y--; else if (move == DOWN) y++;

5 else if (move == LEFT) x--; else if (move == RIGHT) x++; public int getrow() return x; public int getcolumn() return y;