CS111 Lab 12 Answers
Task 1: SquareBuggleWorld
class SquareBuggle extends Buggle {
// Instance Variables
private int sizeOfLastSquare;
private int numberSquaresDrawn;
// Default Constructor
public SquareBuggle () {
// Initialize the instance variables.
sizeOfLastSquare = 0;
numberSquaresDrawn = 0;
}
// Draw a square with sides of length size, for size>0.
// Drops the number of squares drawn in the initial corner when done.
public void square (int size) {
if (size > 0) { // draw a square
if (size == 1) { // square of size one
paintCell(getColor()); // paint cell the color of the Buggle
} else { // size > 1
for (int i = 0; i < 4; i++) { // draw side and turn left four times
forward(size - 1);
left();
}
}
sizeOfLastSquare = size; // store the size of the square drawn
numberSquaresDrawn = numberSquaresDrawn + 1; // increment the number of squares drawn
dropInt(numberSquaresDrawn); // drop number in corner of square
}
}
// Draw the same square as the last square drawn (same side length).
public void repeat () {
square(sizeOfLastSquare);
}
}
Task 2: HurdleWorld
class Hurdler extends Buggle {
public int numHurdles;
public Hurdler() {
numHurdles = 0;
}
public void running() {
if (atFinishLine()) {
//do nothing
} else if (isFacingWall()) {
jumpHurdle();
numHurdles = numHurdles + 1;
running();
} else {
forward();
running();
}
}
public boolean atFinishLine() {
// Return true if buggle is facing wall (as opposed to hurdle) and false otherwise.
// Should leave buggle in same position and heading as when it starts.
// Should not leave any marks behind.
boolean result;
if (isFacingWall()) {
brushUp();
left();
forward();
right();
result = isFacingWall();
left();
backward();
right();
brushDown();
} else {
result = false;
}
return result;
}
public void jumpHurdle() {
left();
forward();
right();
forward();
right();
forward();
left();
}
}
Task 3: BankAccount
BankAccount interface
public interface BankAccount {
//Constructor with no money in savings and checking
public int getSavings();
public int getChecking();
public int getTotal();
public void depositToSavings (int account);
public void transferFromSavingsToChecking(int account);
public void withdrawFromChecking(int amount);
}
SimpleBankAccount1
Implementing BankAccount as three instance integer instance variables savings,
checking, and total.
public class SimpleBankAccount1 implements BankAccount {
// Instance Variables
private int savings, checking; // can declare variables of same type on same line
private int total; // or on a separate line
// Default Constructor
public SimpleBankAccount1 () {
savings = 0;
checking = 0;
total = 0;
}
// Public Instance Methods
public int getSavings () {
return savings;
}
public int getChecking () {
return checking;
}
public int getTotal () {
return total;
}
public void depositToSavings (int amount) {
savings = savings + amount;
total = total + amount;
}
public void transferFromSavingsToChecking (int amount) {
if (amount <= savings) {
savings = savings - amount;
checking = checking + amount;
}
}
public void withdrawFromChecking (int amount) {
if (amount <= checking) {
checking = checking - amount;
total = total - amount;
}
}
}
SimpleBankAccount2
Implementing BankAccount as two instance integer instance variables savings and total.
public class SimpleBankAccount2 implements BankAccount {
// Instance Variables
private int savings, total;
// Default Constructor
public SimpleBankAccount2 () {
savings = 0;
total = 0;
}
// Public Instance Methods
public int getSavings () {
return savings;
}
public int getChecking () {
return total - savings;
}
public int getTotal () {
return total;
}
public void depositToSavings (int amount) {
savings = savings + amount;
total = total + amount;
}
public void transferFromSavingsToChecking (int amount) {
if (amount <= savings) {
savings = savings - amount;
}
}
public void withdrawFromChecking (int amount) {
if (amount <= getChecking()) {
total = total - amount;
}
}
}
SimpleBankAccount3
Implementing BankAccount as an IntList accountInfo with three nodes which
hold the values of the savings account, checking account, and total of both accounts.
public class SimpleBankAccount3 implements BankAccount {
// Instance Variables
private IntList accountInfo;
// Default Constructor
public SimpleBankAccount3 () {
accountInfo = prepend(0, prepend(0, prepend(0, empty())));
}
// Public Instance Methods
public int getSavings () {
return head(accountInfo);
}
public int getChecking () {
return head(tail(accountInfo));
}
public int getTotal () {
return head(tail(tail(accountInfo)));
}
public void depositToSavings (int amount) {
accountInfo = prepend(getSavings()+amount,
prepend(getChecking(),
prepend(getTotal()+amount, empty())));
}
public void transferFromSavingsToChecking (int amount) {
if (amount <= getSavings()) {
accountInfo = prepend(getSavings()-amount,
prepend(getChecking()+amount, tail(tail(accountInfo))));
}
}
public void withdrawFromChecking (int amount) {
if (amount <= getChecking()) {
accountInfo = prepend(getSavings(),
prepend(getChecking()-amount,
prepend(getTotal()-amount, empty())));
}
}
}
SimpleBankAccount4
Implementing BankAccount as an integer array accountInfo with three slots which
hold the values of the savings account, checking account, and total of both accounts.
public class SimpleBankAccount4 implements BankAccount {
// Instance Variables
private int[] accountInfo;
// Default Constructor
public SimpleBankAccount4 () {
accountInfo = new int[3];
for (int i = 0; i < 4; i++) { // initialize values in array; actually not necessary
accountInfo[i] = 0; // since Java initializes integers to zero
}
}
// Public Instance Methods
public int getSavings () {
return accountInfo[0];
}
public int getChecking () {
return accountInfo[1];
}
public int getTotal () {
return accountInfo[2];
}
public void depositToSavings (int amount) {
accountInfo[0] = getSavings() + amount;
}
public void transferFromSavingsToChecking (int amount) {
if (amount <= getSavings()) {
accountInfo[0] = getSavings() - amount;
accountInfo[1] = getChecking() + amount;
}
}
public void withdrawFromChecking (int amount) {
if (amount <= getChecking()) {
accountInfo[1] = getChecking() - amount;
accountInfo[2] = getSavings() + getChecking();
}
}
}
SimpleBankAccount5
Implementing BankAccount as a Vector accountInfo with two elements
which hold the values of the savings and checking accounts.
public class SimpleBankAccount5 implements BankAccount {
// Instance Variables
private Vector accountInfo;
// Default Constructor
public SimpleBankAccount5 () {
accountInfo = new Vector();
accountInfo.addElement(new Integer(0));
accountInfo.addElement(new Integer(0));
}
// Public Instance Methods
public int getSavings () {
return ((Integer)accountInfo.elementAt(0)).intValue();
}
public int getChecking () {
return ((Integer)accountInfo.elementAt(1)).intValue();
}
public int getTotal () {
return getSavings() + getChecking();
}
public void depositToSavings (int amount) {
accountInfo.setElementAt(new Integer(getSavings()+amount), 0);
}
public void transferFromSavingsToChecking (int amount) {
if (amount <= getSavings()) {
accountInfo.setElementAt(new Integer(getSavings()-amount), 0);
accountInfo.setElementAt(new Integer(getChecking()+amount), 1);
}
}
public void withdrawFromChecking (int amount) {
if (amount <= getChecking()) {
accountInfo.setElementAt(new Integer(getChecking()-amount), 1);
}
}
}