Java how to return two variables?

Question

after c++ i am trying to learn some java, and i have a question about the code i have been working on. I am working on a Fraction class and i got stuck in reduce section. Since the method did not let me to return both "num" and "den", I had to return "n" This is my method

public double reduce() {
    int n = num;
    int d = den;

    while (d != 0) {
        int t = d;
        d = n % d;
        n = t;
    }
    int gcd = n;

    num /= gcd; //num = num / greatestCommonDivisor
    den /= gcd; //den = den / greatestCommonDivisor
    return n;
}

I am trying to do "return num, den;" however it does not let me.

and this is what i get

to reduced test for  100/2 is 2.0
to reduced test for  6/2 is 2.0

when i run

System.out.println("to reduced test for  " + f4.toString() + " is " + f4.reduce());
System.out.println("to reduced test for  " + f6.toString() + " is " +f6.reduce());

Why do i get the 2 when when i am supposed to get 50/1 and 3/1 ? If the IDE let me return num and den at the same time, would that have fixed it?

Thanks

This is a n-times duplicate, here: http://stackoverflow.com/questions/8557716/how-to-return-multiple-values-in-java or here: http://stackoverflow.com/questions/16609269/best-practice-for-returning-multiple-values-in-java — Raul Guiu, Feb 05 '14 at 23:55

score 3 · Accepted Answer · answered Feb 05 '14 at 23:53

3

Java has no native way of doing this, you only can return one Object or primitive. This leaves you two options:

Return an array with length 2.

public int[] reduce()
{
    ...
    return new int[]{num, den};
}

Return an object of a wrapper class containing the two numbers.

public Fraction reduce()
{
    ...
    return new Fraction(num, den);
}

answered Feb 05 '14 at 23:53

Martijn Courteaux

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Thanks so much, return new Fraction(num, den) did the trick (= – UniQuadrion Feb 06 '14 at 00:30

score 0 · Answer 2 · answered Feb 05 '14 at 23:55

0

It looks like your reduce method is modifying the object. It's unclear what exactly you want to return. If you want the fraction to return itself, then return this;, with the method returning a Fraction in the declaration.

answered Feb 05 '14 at 23:55

rgettman

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Java how to return two variables?

2 Answers2