1. Add two constructors to your fraction class. One should be a default constructor which creates the fraction 0/1. The other should accept numerator and denominator arguments.

2. Add a method dblValue to your fraction class which returns the double precision approximate value of the fraction. Eg, if a client has a fraction f which represents 1 / 2 then f.dblValue() should return the double number 0.5.

3. Add a private method simplify to your fraction class which converts the fraction to its simplest form. For example, the fraction 20/60 should be stored as 1/3.

4. Add a toString method to your fraction class which returns the fraction as a String in the form “x/y”, where x and y are numerator and denominator respectively.

5. Write a client program which allows the user to add up any number of non-zero fractions. The program should display the running total as an exact fraction (in simplified form as x/y) and as an approximate double value. The user can finish by entering a fraction which represents zero.

NOTE:  Fraction class from code below

Program in NETBEANS

package com.frac;
import java.util.Scanner;

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class Fraction
{
    // question 1
    private int numerator;
    private int denominator ;

    // Function to get input
    public void get_input( int n ,int d)
    {
        // for question 4
        if (d == 0){
            d = 1;
        } else if (d<0){
            n *= -1;
            d *= -1;
        }
        numerator=n;
        denominator=d;
        reduce();
    }

    private int gcd(int n1, int n2){
        if (n2 == 0){
            return n1;
        }
        return gcd(n2, n1 % n2);
    }

    // question 2
    public boolean isZero(){
        return numerator == 0;
    }

    // question 3
    public boolean equals(Fraction o){
        return numerator == o.numerator && denominator == o.denominator;
    }

    // question 3
    public Fraction add(Fraction o){
        int denom = denominator * o.denominator;
        int num = (denom / denominator) * numerator + (denom / o.denominator) * o.numerator;
        Fraction res = new Fraction();
        res.numerator = num;
        res.denominator = denom;
        res.reduce();
        return res;
    }

    public int getDenominator() {
        return denominator;
    }

    public int getNumerator() {
        return numerator;
    }

    public void setDenominator(int denominator) {
        if (denominator < 0){
            numerator *= -1;
            denominator *= -1;
        } else if (denominator == 0){
            denominator = 1;
        }
        this.denominator = denominator;
        reduce();
    }

    public void setNumerator(int numerator) {
        this.numerator = numerator;
        reduce();
    }

    // Function to print output
    public void printOutput ()
    {
        System.out.println("Fraction is :"+ numerator +"/" + denominator);
    }

    private void reduce(){
        int gd = this.gcd(this.numerator, this.denominator);
        numerator = numerator / gd;
        denominator = denominator / gd;
    }

}

class Mainprogram {
    // Declare a Main Function to get inputs and call fraction class methods
    public static void main(String args[])
    {
        Scanner scn=new Scanner(System.in);
        // Code 1 to check repeated character in string
        // Take String From User
        System.out.println ( "Enter the String");
        String str = scn.next();
        // Flg is variable that will change if any same character
        boolean flag=true;
        for (int i = 0; i < str.length(); i++)
            for (int j = i + 1; j < str.length(); j++)
                if (str.charAt(i) == str.charAt(j))
                    flag=false;
        // if flag = false then string has repeated characters
        if (!flag)
            System.out.println("The String " + str + " has repeated characters");
        else
            System.out.println("The String " + str + " has no repeated characters");
        // Now from here we Code 2 of fraction class has started i.e FractionFDemo .java
        // make a object of Fraction Class
        Fraction obj = new Fraction();
        Fraction obj2 = new Fraction();
        int n,d;
        // Repeat the loop until numerator is negative
        do
        {
            // Take numerator and denominator from user
            System.out.println ( "Enter the numerator and denominator ");
            n = scn.nextInt();
            d = scn.nextInt();
            // If numerator>0 then only call class methods
            obj.get_input(n,d);
            if(n>0)
            {
                // Call methods to print the Fraction
                obj.printOutput();

                System.out.println ( "Enter the numerator and denominator ");
                n = scn.nextInt();
                d = scn.nextInt();

                obj2.get_input(n, d);
                Fraction sum = obj.add(obj2);
                // question 3
                // check equality
                System.out.println("isEqual: "+ obj.equals(obj2));
                // calculate sum
                System.out.println("Sum = ");
                sum.printOutput();
            }

        } while(!obj.isZero()); // question 2


    }
}