Question

I am trying to write a class Rational that had a few methods relating to adding, subtracting, etc. I want to make it so that within the constructor, I add the values to the private variables and find the GCD to find simplify the fraction. The problem I run into is with my if statements. I want to check if the numbers within the object parameter are negative so I use the if statement to check. The only problem is when I run the program, it doesn’t give me a negative value i.e. I have Rational p = new Rational(-24, 48) and it only returns 1/2.

public class TestRational {

    public static void main(String... args) {
        Rational p = new Rational(-24, 48);
    }

    public Rational(long a, long b){
        numerator = a;
        denominator = b;
        boolean isNegative = false;
        if (numerator*denominator < 0)
            isNegative = true;
        long gd = gcd(numerator, denominator);
        numerator /= gd;
        denominator /= gd;
        if (isNegative)
            numerator = -numerator;;
    }

    private long gcd(long p, long q){
        //checks to see if numerator greater than denominator
        if(p<q)
            return gcd(q,p);
        if(Math.abs(q) == 0)
            return p;
        long remainder = Math.abs(p)%Math.abs(q);
        return gcd(Math.abs(q), Math.abs(remainder));
    }
}

Answer 1

You dont need this

if (isNegative)
 numerator = -numerator;;

So the constructor becomes

public Rational(long a, long b){
 numerator = a;
 denominator = b;
 boolean isNegative = false;
 if (numerator*denominator < 0)
 isNegative = true;
 long gd = gcd(numerator, denominator);
 numerator /= gd;
 denominator /= gd;
}

Hope it works …