Question

CIT-111 Homework #5, Part A                                    Chapter 5, part 1 and alternate part 2 (page 341)

A breakdown of the problem is as follows:

• Class name:                        Money
  
• Instance variables:           private, integer:                dollars, cents
  
• Constructor methods:    Money () – sets dollars and cents both to zero
  
                                                  Money (int bucks) – sets dollars to bucks, cents to zero
  
                                                  Money (int buck, int pennies) – sets dollars to bucks, cents to pennies
  
• Accessor methods:          getDollar () – returns value of dollars for the object
                                                  getCent () – returns value of cents for the object
  
• Mutator methods:           setDollar (int bucks) – sets the value of dollars to bucks
                                                  setCent (int pennies) – sets the value of cents to pennies
                                                 
                                                  void add (Money pmt1) – public method adds the argument’s
                                                  dollar and cents to the instance variables
                                                 
                                                  Money add (Money pmt1, Money pmt2) – static method returns a
                                                  Money object with the sum of the dollars and cents of the 2 arguments
  
                                                  void minus (Money pmt1) – public method subtracts the argument’s
                                                  dollar and cents from the instance variables
  
                                                  Money minus (Money pmt1, Money pmt2) – static method returns a
                                                  Money object with the difference of the dollars and cents of the 2
                                                  arguments
  
• Other methods:                 equals – determines if argument (object of class Money) is equal to
                                                  the value of dollars and cents for this object
                                                  toString – returns dollars and cents as a string that includes $ and
                                                  decimal point

EXTRA CREDIT: (some or all three)

1. When setting dollars and cents, if the values are negative, use a value of zero. If cents is greater than 99, use a value of 99.
2. When adding cents, if the result is greater than 99 adjust dollars and cents appropriately.
3. When subtracting cents and getting a negative number, adjust dollars (if a positive number) and store cents result as a positive number. If subtracting dollars and getting a negative number, set dollars result to 0.

Use the driver program MoneyDemo (download from Blackboard) to test your Money class methods.

Answer 1

Solution:

CODE ( money.java )

public class Money {

   private int dollars, cents;
  
   public Money() {
       this.dollars = 0;
       this.cents = 0;
   }
  
   public Money(int bucks) {
       this.dollars = bucks;
       this.cents = 0;
   }

   public Money(int bucks, int pennies) {
       this.dollars = bucks;
       this.cents = pennies;
   }

   public int getDollars() {
       return dollars;
   }

   public void setDollars(int bucks) {
       if(bucks < 0) {
           this.dollars = 0;
       }
       else
           this.dollars = bucks;
   }

   public int getCents() {
       return cents;
   }

   public void setCents(int pennies) {
       if (pennies < 0) {
           this.cents = 0;
       }
       else
           this.cents = pennies;
   }
  
   public void add(Money pmt1) {
       this.dollars += pmt1.cents / 100 + pmt1.dollars;
       this.cents += pmt1.cents % 100;
   }
  
   static Money add( Money pmt1, Money pmt2 ) {
       int dollars, cents, total_cents;
       total_cents = pmt1.cents + pmt2.cents;
       dollars = pmt1.dollars + pmt2.dollars + total_cents / 100;
       cents = total_cents % 100;
       return new Money(dollars, cents);
   }
  
   public void minus(Money pmt1) {
       if (pmt1.cents > this.cents) {
           this.cents += 100 - pmt1.cents;
           this.dollars += pmt1.dollars - 1;
       }
       else {
           this.cents -= pmt1.cents;
           this.dollars += pmt1.dollars;
       }
   }
  
   static Money minus(Money pmt1, Money pmt2) {
       int dollars, cents;
       if (pmt1.dollars > pmt2.dollars) {
           if(pmt1.cents > pmt2.cents) {
               cents = pmt1.cents - pmt2.cents;
               dollars = pmt1.dollars - pmt2.dollars;
           }
           else {
               cents = pmt2.cents - pmt1.cents;
               dollars = pmt1.dollars - pmt2.dollars - 1;
           }
       }
       else {
           if(pmt2.cents > pmt1.cents) {
               cents = pmt2.cents - pmt1.cents;
               dollars = pmt2.dollars - pmt1.dollars;
           }
           else {
               cents = pmt1.cents - pmt2.cents;
               dollars = pmt2.dollars - pmt1.dollars - 1;
           }
       }
       if(dollars < 0) dollars = 0;
       return new Money(dollars, cents);
   }

   public boolean equals(Money other) {
       if (cents != other.cents)
           return false;
       if (dollars != other.dollars)
           return false;
       return true;
   }

   @Override
   public String toString() {
       return "Money [$" + dollars + "." + cents + "]";
   }
  
      
}

Sample tester code :

( MoneyTester.java )

import Money;

public class MoneyTester {

   public static void main(String[] args) {

       Money money1 = new Money(20, 2);
       Money money2 = new Money(32, 87);
       Money money3 = new Money(32, 87);
      
       System.out.println("Money 1 : " + money1);
       System.out.println("Money 2 : " + money2);
      
       System.out.println("Sum of money1 and money2 is " + Money.add(money1, money2));
       System.out.println("Differnce of money1 and money2 is : " + Money.minus(money1, money2));
      
       System.out.println("Money1 and Money2 are equal : " + money1.equals(money2));
       System.out.println("Money2 and Money3 are equal : " + money2.equals(money3));
   }

}

Sample Output ( Sample Run ) :