CPE 103 Homework Solutions

public class Combolock
{
    private int num1;
    private int num2;
    private int num3;
    public Combolock ( int a, int b, int c)
    {
        num1 = a;
        num2 = b;
        num3 = c;
    }
    //returns true if the proper combination is given
    public boolean open ( int a, int b, int c)
    {
        return ( ( a == num1 ) && ( b == num2 ) && (c == num3 ) );
    }
    public boolean changeCombo( int a, int b, int c, int newA,
                                int newB, int newC )
    {
        if ( open( a, b, c) )
        {
            num1 = newA;
            num2 = newB;
            num3 = newC;
            return true;
        }
        return false;
    }

public static void printArray(int [][] arr)
{
    for (int row = 0; row < arr.length; row++)
    {
        for (int col = 0; col < arr[row].length; col++)
            System.out.print(String.format("%5d", arr[row][col]));
        System.out.println();
    }
}

public class BinaryArray
{
    private boolean [] arr = null;
    public BinaryArray(String init)
    {
        arr = new boolean[init.length()];
        for (boolean value : arr)
            value = false;
        for (int ch = 0; ch < init.length(); ch++)
        {
            boolean val = false;
            if (init.charAt(ch) == 'T')
                val = true;
            arr[ch] = val;
        }
    }
    public int size()
    {
        return arr.length;
    }
    public String toString()
    {
        String result = "";
        for (int i = 0; i < arr.length; i++)
            result += arr[i] + " ";
        return result;
    }
    public boolean get(int location)
    {
        return arr[location];
    }

    public void set(int location, boolean value)
    {
        arr[location] = value;
    }
}

Base( int pub, int pri, int pro )
{
    bPublic = pub; bPrivate = pri; bProtect = pro;
}
 
Derived( int bpub, int bpri, int bpro, int dpub, int dpri )
{
    super( bpub, bpri, bpro );
    dPublic = dpub; dPrivate = dpri;
}

class Person implements Comparable
{
    public int compareTo(Object rhs)
    {
        Person p2 = (Person) rhs;
        return (name.compareTo(p2.name));
    }
}

/**
 * Enum for a baseball player position
 * 
 */
public enum Player
{
     Pitcher, Catcher, Firstbase, Secondbase, Shortstop, Thirdbase, Leftfield, Centerfield, Rightfield;
     
}

import java.util.*;
/**
 * PlayerClient is a driver for the Player enum.
 */
public final class PlayerClient
{
    public static void main(String[] args)
    {
        // show all the players, in order. 
        for (Player p: Player.values())
        {
            System.out.println(p);
        }
        //Read a string from the user that represents a player, and creates an enum value.
        Scanner console = new Scanner(System.in);
        String input = console.nextLine();
        try 
        {
            Player player = Player.valueOf(input);
            // If the enum value is a Pitcher, print "Strike", otherwise print "Ball".
            if (player.equals(Player.Pitcher))
            {
                System.out.println("Strike");
            }
            else
            {
                System.out.println("Ball");
            }
        }
        catch (IllegalArgumentException ex)
        {
            System.out.println("Input is not a player.");
        }
    }
}

Apple( int pub, int pri, int pro, int lim )
{
    aPublic = pub; aPrivate = pri; aProtect = pro; aLimited = lim
}

Gala( int apub, int apri, int apro, int gpub, int gpri )
{
    super( apub, apri, apro );
    gPublic = gpub; gPrivate = gpri;
}

1. An integer can be assigned a value other than 1 to 9.  Use an enum instead.
2. Checkerboards are two-dimensional, so use a 2-d array.
3. Never represent monetary values with floating point data types.  Use int, BigDecimal, or a Money ADT.
4. Arraylist allows items to be inserted in the middle, the queue of cars doesn't.  Use a Queue ADT.
5. Song durations are never negative.  Use a Natural ADT or unsigned integer ADT.
6. Strings can't do arithmetic calculations, which are common with dates.  Use a java Date.

 0
 1 105
 2 639  
 3 718 
 4 692
 5 538
 6 799
 7 254
 8 277
 9 512
10 101 
11 375
12 822

 0 277
 1
 2 639
 3 718
 4 692
 5 538
 6 800
 7 254
 8 255
 9 100
10 101
11 375
12

	 public static long sumOfDigits(long x)
	 {
		  if (x < 10)
		  {
			   return x;
		  }	   
		  return (x % 10) + sumOfDigits( x / 10 );
	 }

Problem 1



A  B -> D

B  A -> C

C  B -> D -> G

D  A -> C -> E -> F

E  D -> F

F  D -> E

G  C



Problem 2

  A B C D E F G
A   1   1
B 1   1
C   1   1     1
D 1   1   1 1
E       1   1
F       1 1
G     1

Problem 3

  1 2 3 4 5 6 7
1   1 1 1
2       1 1
3           1
4     1     1 1
5       1     1
6
7           1
 

1.  Breadth-first
A  B I C H D G E F
B A C H I D G E F
E  D C F B G A H I
F  D G C E H B I A