HOMEWORK 3 - SAMPLE ANSWERS

1. (a) true
   (b) false
   (c) false
   (d) true

2. (a)              |
                    V
                   / \
               T  /   \  F
              ___/ x<0 \___
             |   \     /   |
             |    \   /    |
             |     \ /     |
             V          -------
            / \        /  "A" /->
        T  /   \  F    -------
       ___/x-y<0\___       |
      |   \     /   |      |
      |    \   /    |      | 
      |     \ /     |      |
      V             V      |
   -------       -------   |
  /  "B" /      /  "C" /   |
  -------       -------    |
      |_____________|      |
             |_____________|
                    |
                    V
(b)
              |
              |
          B   |    A
              |
     -------------------
             /|
        B   / |    A
           /  |
          / C |


3. (a) if ((age <= 25) || (veteran == true))
   (b) if (!((age > 25) && (veteran == false)))
   (c) if ((age <= 25) || veteran)

4. average >= 90
   average >= 80
   average < 60
   average >= 70

5. (a) The else matches with the 2nd if.
       if (x > 0)
           if (y > 0)
               z = 5;
           else
               z = 3;
   (b) 
       if (x > 0) {
           if (y > 0)
               z = 5;
       } else
               z = 3;

6.

import java.util.*; 
public class MusicSuggestor { 
	public static void main (String[] args) { 
 
	Scanner scan = new Scanner(System.in); 
                         
	// Prompt and read in user input. 
	// Convert userInput to uppercase. 
	System.out.println("Please enter a musical genre: "); 
	String userInput = scan.nextLine().toUpperCase(); 
                         
	// Must use .equals on String instead of ==. 
	if (userInput.equals("POP")) 
		System.out.println("Kelly Clarkson"); 
	else if (userInput.equals("RAP")) 
		System.out.println("Kanye West"); 
	else if (userInput.equals("COUNTRY"); 
		System.out.println("Kenny Chesney"); 
	else 
		System.out.println(""No suggestion available."); 
	} 
} 

7. 
(a) public static void randomMove() {
	int randNum = (int)(Math.random() * 100) + 1;
	if (randNum % 2 == 0) {
		Robot.turnLeft();
		Robot.turnLeft();
		Robot.turnLeft();
	} else {
		Robot.turnLeft();
		Robot.turnLeft();
		Robot.move();
		Robot.turnLeft();
		Robot.turnLeft();
	}
    }

(b) public static void fancyMove() {
	if (!Robot.onDark()) {
		if (Robot.frontIsClear()) {
			Robot.move();
		}
		else {
			Robot.turnLeft();
		}
	}
	else {
		Robot.turnLeft();
		Robot.turnLeft();
	}
    }