Week 9 Practice Problems
[Topic: Objects and Classes]
public class Main {
public static void main(String[] args) {
Halloween you = new Halloween();
you.buyCandy(50);
for (int i = 1; i <= 5; i++) {
you.giveCandy(i);
}
System.out.printf("I end the night with %d piece(s) of candy.%n", you.getCandy());
}
}
public class Halloween {
private int candy;
public Halloween() {
this.candy = 0;
}
public Halloween(int candy) {
this.candy = candy;
}
public int getCandy() {
return this.candy;
}
public int buyCandy(int amount) {
if (amount < 0) {
System.out.println("Silly you, you can't buy negative pieces of candy :)");
} else {
System.out.printf("You went out and bought %d piece(s) of candy.%n", amount);
this.candy = this.candy + amount;
}
return this.candy;
}
public int giveCandy(int amount) {
if (amount < 0) {
System.out.println("Silly you, you can't give negative pieces of candy :)");
} else {
System.out.printf("You gave out %d piece(s) of candy.%n", amount);
this.candy = this.candy - amount;
}
return this.candy;
}
public void trickOrTreat(boolean treat) {
if (treat) {
System.out.printf("Here are %d pieces of candy!%n", 5);
} else {
System.out.printf("You have been tricked and had %d pieces of candy stolen from you :(%n", 2);
}
}
}
You went out and bought 50 piece(s) of candy.
You gave out 1 piece(s) of candy.
You gave out 2 piece(s) of candy.
You gave out 3 piece(s) of candy.
You gave out 4 piece(s) of candy.
You gave out 5 piece(s) of candy.
I end the night with 35 piece(s) of candy.
public class Main {
public static void main(String[] args) {
CoinMachine cm = new CoinMachine(50, 50, 50, 50);
cm.giveChange(50.00, 49.99);
cm.giveChange(35.00, 27.99);
cm.giveChange(32.00, 25.00);
cm.giveChange(1.23, 0.95);
cm.giveChange(0.75, 0.55);
cm.giveChange(33.33, 27.75);
cm.giveChange(0.92, 0.50);
cm.inStorage();
}
}
public class CoinMachine {
private int quarter;
private int dime;
private int nickel;
private int penny;
public CoinMachine() {
this.quarter = 0;
this.dime = 0;
this.nickel = 0;
this.penny = 0;
}
public CoinMachine(int quarter, int dime, int nickel, int penny) {
this.quarter = quarter;
this.dime = dime;
this.nickel = nickel;
this.penny = penny;
}
private double round(double amount) {
return Math.round(amount * 100) / 100.0;
}
public void giveChange(double payment, double price) {
if (payment < price) {
System.out.println("Customer did not pay enough.");
return;
}
// keep count of amount of each coin that is going to be given to the user
int q = 0;
int d = 0;
int n = 0;
int p = 0;
// payment - how much the user pays
// price - their total for the purchase
// TODO: implement this
double change = this.round(payment - price);
}
public void inStorage() {
System.out.printf("%-10s%d%n", "25¢", this.quarter);
System.out.printf("%-10s%d%n", "10¢", this.dime);
System.out.printf("%-10s%d%n", "5¢", this.nickel);
System.out.printf("%-10s%d%n", "1¢", this.penny);
}
public void addQuarter(int count) {
if (count < 0) {
System.out.println("Negative not allowed.");
} else {
this.quarter = this.quarter + count;
}
}
public void addDime(int count) {
if (count < 0) {
System.out.println("Negative not allowed.");
} else {
this.dime = this.dime + count;
}
}
public void addNickel(int count) {
if (count < 0) {
System.out.println("Negative not allowed.");
} else {
this.nickel = this.nickel + count;
}
}
public void addPenny(int count) {
if (count < 0) {
System.out.println("Negative not allowed.");
} else {
this.penny = this.penny + count;
}
}
}
while (change >= 0.25 && this.quarter > 0) {
change = this.round(change - 0.25);
q++;
this.quarter--;
}
while (change >= 0.10 && this.dime > 0) {
change = this.round(change - 0.10);
d++;
this.dime--;
}
while (change >= 0.05 && this.nickel > 0) {
change = this.round(change - 0.05);
n++;
this.nickel--;
}
while (change >= 0.01 && this.penny > 0) {
change = this.round(change - 0.01);
p++;
this.penny--;
}
if (change > 0) {
System.out.println("Not enough coins");
} else {
System.out.println("Coins used:");
System.out.println(q + " Quarter(s)");
System.out.println(d + " Dime(s)");
System.out.println(n + " Nickel(s)");
System.out.println(p + " Penny(s)");
}
Expected Output
Coins used:
0 Quarter(s)
0 Dime(s)
0 Nickel(s)
1 Penny(s)
Coins used:
28 Quarter(s)
0 Dime(s)
0 Nickel(s)
1 Penny(s)
Coins used:
22 Quarter(s)
15 Dime(s)
0 Nickel(s)
0 Penny(s)
Coins used:
0 Quarter(s)
2 Dime(s)
1 Nickel(s)
3 Penny(s)
Coins used:
0 Quarter(s)
2 Dime(s)
0 Nickel(s)
0 Penny(s)
Coins used:
0 Quarter(s)
31 Dime(s)
49 Nickel(s)
3 Penny(s)
Coins used:
0 Quarter(s)
0 Dime(s)
0 Nickel(s)
42 Penny(s)
25¢ 0
10¢ 0
5¢ 0
1¢ 0