Update variables in for loop in post increment

Question

I am working on simple example.Initially taking the value of a as 1 and b as 2. I am calling method to do an update, when I print this a and b. It will be 1 and 2 as expected. But I should update this a and b in each loop, How can I do this?I am getting thought of returning as list. Is there a simple way to accomplish it?

public class UpdateTest {

    public static void main(String[] args) {
        int a=1;
        int b=2;
        for (int i = 0; i < 5; i++) {
            update(a,b);
        }

       System.out.println(a+"------"+b);
    }

    private static void update(int a, int b) {
        // TODO Auto-generated method stub
        for (int i = 0; i < 10; i++) {
            a++;
            b++;
        }
    }

}

@ElliottFrisch I think he knows that and is just wonder how to easily return 2 values (the values of a and b) — ParkerHalo
– ParkerHalo, Commented Nov 9, 2015 at 15:54

Manos Nikolaidis · Accepted Answer · 2015-11-09 15:55:41Z

2

You can put the values in a class e.g.

class Pair {
    int a, b;
    Pair(int a, int b) {
        this.a = a;
        this.b = b;
    }
}

Initialize it like this

Pair pair = new Pair(1, 2);

Then modify the update method accordingly

private static void update(Pair pair) {
    for (int i = 0; i < 10; i++) {
        pair.a++;
        pair.b++;
    }
}

edited Nov 9, 2015 at 15:55

answered Nov 9, 2015 at 15:53

Manos Nikolaidis

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Comments

ParkerHalo · Accepted Answer · 2015-11-09 15:59:18Z

1

Its not very nice but will do the job: You can simply return an array containing the values of a and b.

public class UpdateTest {

    public static void main(String[] args) {
        int a=1;
        int b=2;
        for (int i = 0; i < 5; i++) {
            int[] ret = update(a,b);
            a = ret[0];
            b = ret[1];
        }

        System.out.println("a= " + a + ", b= " +b);
    }

    private static int[] update(int a, int b) {
        for (int i = 0; i < 10; i++) {
            a++;
            b++;
        }
        int[] ret = {a,b};
        return ret;
    }
}

answered Nov 9, 2015 at 15:59

ParkerHalo

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2 Comments

FredK Over a year ago

Why the loop instead of a += 10 and b+= 10 ?

ParkerHalo Over a year ago

I just took that part from the sourcecode the OP provided! Of course you're right, faster would be a+=10; b+=10

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