Question

Given the main method of a driver class, write a Fraction class. Include the following instance methods:

add,

multiply,

print,

printAsDouble,

and a separate accessor method for each instance variable.

• 1. Write a Fraction class that implements these methods:
• add ─ This method receives a Fraction parameter and adds the parameter fraction to the calling object fraction.
• multiply ─ This method receives a Fraction parameter and multiplies the parameter fraction by the calling object fraction.
• print ─ This method prints the fraction using fraction notation (1/4, 21/14, etc.)
• printAsDouble ─ This method prints the fraction as a double (0.25, 1.5, etc.)

Separate accessor methods for each instance variable in the Fraction class.

Provide a driver class, FractionDemo,   that demonstrates this Fraction class. The driver class should contain this main method:

public static void main(String[] args)

{

Scanner stdIn = new Scanner(System.in);

Fraction c, d, x;       // Fraction objects

System.out.println("Enter numerator; then denominator.");

c = new Fraction(stdIn.nextInt(), stdIn.nextInt());

c.print();

System.out.println("Enter numerator; then denominator.");

d = new Fraction(stdIn.nextInt(), stdIn.nextInt());

d.print();

x = new Fraction();     // create a fraction for number 0

System.out.println("Sum:");

x.add(c).add(d);

x.print();

x.printAsDouble();

x = new Fraction(1, 1); // create a fraction for number 1

System.out.println("Product:");

x.multiply(c).multiply(d);

x.print();

x.printAsDouble();

System.out.println("Enter numerator; then denominator.");

x = new Fraction(stdIn.nextInt(), stdIn.nextInt());

x.printAsDouble();

} // end main

Note that this demonstration driver does not call the accessor methods. That’s OK.   Accessor methods are often implemented regardless of whether there’s an immediate need for them. That’s because they are very useful methods in general and providing them means that future code can use them when the need arises.

Sample session:

Enter numerator; then denominator.

5

8

5/8

Enter numerator; then denominator.

4

10

4/10

Sum:

82/80

1.025

Product:

20/80

0.25

Enter numerator; then denominator.

6

0

infinity

2. Modify the code so that it can handle negative numerators and negative denominators, and provide a helping method that performs fraction reduction.

Sample session using negative numbers and reduction:

Enter numerator; then denominator.

-5

-8

5/8

Enter numerator; then denominator.

4

-10

-2/5

Sum:

9/40

0.225

Product:

-1/4

-0.25

Enter numerator; then denominator.

0

-0

indeterminate

Answer 1

Fraction.java

public class Fraction {
   private int numerator;
   private int denominator;
  
   Fraction(){
       numerator = 0;
       denominator = 1;
   }
   Fraction(int n, int d){
       //If both numerator and denominator are negative
       if(n<0 && d<0) {
           this.numerator = -n;
           this.denominator = -d;
       }
       //If numerator is positive, denominator is negative
       else if (n>0 && d<0){
           numerator = -n;
           denominator = -d;
       }
       //Otherwise
       else {
           numerator = n;
           denominator = d;
       }
   }
  
   public int getNumerator() {
       return numerator;
   }
   public int getDenominator() {
       return denominator;
   }
        //Adds Fraction f to the current Fraction object, and returns new Fraction
   public Fraction add(Fraction f) {
       int num = this.numerator*f.denominator + this.denominator*f.numerator;
       int denom = this.denominator*f.denominator;
       this.numerator = num;
       this.denominator = denom;
       return this;
   }
   //Multiplies Fraction f to the current Fraction object, and returns new Fraction
   public Fraction multiply(Fraction f) {
       int num = this.numerator * f.numerator;
       int denom = this.denominator * f.denominator;
       this.numerator = num;
       this.denominator = denom;
       return this;
   }
      
   public void print() {
       if(numerator == 0 && denominator == 0)
           System.out.println("Indeterminate");
       else if (denominator==0)
           System.out.println("Infinity");
       else
           System.out.println(numerator + "/" + denominator);
   }
  
   public void printAsDouble() {
       System.out.println((double)numerator/denominator);
   }
}

FractioDemo.java

import java.util.Scanner;

public class FractionDemo {

   public static void main(String[] args) {
       Scanner stdIn = new Scanner(System.in);
       Fraction c, d, x;       // Fraction objects
       System.out.println("Enter numerator; then denominator.");
       c = new Fraction(stdIn.nextInt(), stdIn.nextInt());
       c.print();
       System.out.println("Enter numerator; then denominator.");
       d = new Fraction(stdIn.nextInt(), stdIn.nextInt());
       d.print();
       x = new Fraction();     // create a fraction for number 0
       System.out.println("Sum:");
       x.add(c).add(d);
       x.print();
       x.printAsDouble();
      
       x = new Fraction(1, 1); // create a fraction for number 1
       System.out.println("Product:");
       x.multiply(c).multiply(d);
       x.print();
       x.printAsDouble();
       System.out.println("Enter numerator; then denominator.");
       x = new Fraction(stdIn.nextInt(), stdIn.nextInt());
       x.printAsDouble();      
   }

}