Question

I have written this code as my answer to an assignment I recieved in AP Computer Science, and my teacher is having my redo this because the answers don’t work. I can only compile it on my machine, so I am relying on my teacher as to what results is produces now, which are below. This assignment is do by midnight, tonight, and the procrastinator I am waited till now to ask for help here, but still, it is VERY much appreciated. Also, it’s my first time on here, so sorry that some of the code isn’t formatted properly. Thanks for the help!

Results ATM

if a = 3/4 and b = 5/6

a.add(b) produces 35/24; This should be 19/12
a.subtract(b) produces 1/0; This should be -1/12
a.divide(b) produces 11/1; This should be 9/10
a.multiply(b) produces 6/-5; This should be 5/8

Here’s the code.

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.border.TitledBorder;

class Fraction{
    private int numer;
    private int denom;
    private Fraction answer;

    //Definition
    public Fraction(int num, int den)
    {
        numer = num;
        denom = den;
        simplify();
    }


    //Simplify
    void simplify()
    {
        int gcd = findGCD(numer, denom);
        numer /= gcd;
        denom /= gcd;
    }


    //GCD Function
    int findGCD(int a, int b)
    { int temp;
        while(b != 0)
        {
            temp = b;
            b = a % b;
            a = temp;
        }
        return a;
    }


    //GetNumerator
    public int getNumer()
    {
        return numer;
    }

    //GetDenominator
    public int getDenom()
    {
        return denom;
    }

    //Fraction Add Method
    Fraction add(Fraction x)
    {
        Fraction answer;

        if(denom == x.denom)
        {
            answer = new Fraction(x.numer + numer, denom);
            }
        else
        {
          int den = denom * x.getDenom();
          int num = numer * x.getNumer();
          num += x.getNumer() * denom;
          answer = new Fraction(num, den);

        }
     return answer;
    }


    //Fraction Subtract Method
    Fraction subtract(Fraction x)
    {
        Fraction answer;

        if(x.denom == denom)
        {
            answer = new Fraction(numer - x.numer, denom);
        }
        else
        {
            int den = denom / x.getDenom();
            int num = numer / x.getNumer();
            num -= x.getNumer() * denom;
            answer = new Fraction(num, den);
        }
        return answer;
    }

    //Fraction Multiply Method
    Fraction multiply(Fraction x)
    {
        Fraction answer;

        if(x.denom == denom)
        {
            answer = new Fraction(numer + x.numer, denom);
        }
        else
        {
            int den = denom + x.getDenom();
            int num = numer + x.getNumer();
            num -= x.getNumer() * denom;
            answer = new Fraction(num, den);
        }
        return answer;
    }

    //Fraction Divide Method
    Fraction divide(Fraction x)
    {
        Fraction answer;

        if(x.denom == denom)
        {
            answer = new Fraction(numer - x.numer, denom);
        }
        else
        {
            int den = denom - x.getDenom();
            int num = numer - x.getNumer();
            num -= x.getNumer() * denom;
            answer = new Fraction(num, den);
        }
        return answer;
    }


    //@Override
    public boolean equals(Fraction x)  
    {
        boolean answer = false;

        if(numer == x.numer && denom == x.denom)
      {
            answer = true;
        }

        return answer;
    }


    //ToString
    public String toString()
    {
    return (Integer.toString(numer) + "/" +
             Integer.toString(denom));
    }


    //Main Method
    public void main(String[]args)
    {
        Fraction a = new Fraction(3,4);
        Fraction b = new Fraction(5,6);
        System.out.println(a.toString());
        System.out.println(b.toString());

        Fraction c = a.add(b);
        System.out.println(c.toString());

        c = a.subtract(b);
        System.out.println(c.toString());

        c = a.divide(b);
        System.out.println(c.toString());

        c = a.multiply(b);
        System.out.println(c.toString());





    }

}

Answer 1

So just one thing to begin : use all the time getDenom(), because in your code sometimes it is getDenom, sometimes denom so ..

For add() method:
You’re wrong in the case where denoms are differents.
You have to do :

denom = this.getDenom() * x.getDenom();
num = this.getNum() * x.getDenom() + x.getNumer() * this.getDenom();
//and check if simplification is possible.
return new Fraction(num,denom);

And it is kind of the same things for others operations. Check you multiply by the good denominator or numerator because it seems it is not the case, and don’t forget to simplify.

Hope it helps