Returning Incremented Numbers in Java

Question

I am trying to solve this "incrementation" problem in a Java code but I can't find myself arriving at a solution:

public class Return {
   public static void main(String[] args) {
    int n = returnn(3);
    System.out.println(n);
   }

   public static int returnn(int n) {
    return n++;
   }
}

I am supposed to return 4 but it is returning 3 instead. Why is that? Also, when I type: return n+=1it works. This is confusing me. Also, what is the difference between n++ and ++n? Any clarification is greatly appreciated.

Please see the bottom section of [the Java tutorial](http://docs.oracle.com/javase/tutorial/java/nutsandbolts/op1.html) on the increment operators. — rgettman, May 07 '14 at 20:15
++n will worj but be warned : the value of n in the function if a copy of the value in main. So return (n+1) will have same effect as the location param n in function returnn is lost once the function returns — tgkprog, May 07 '14 at 20:18
Just `return n+1;` There is no need to increment the local variable. — clcto, May 07 '14 at 20:18

score 3 · Answer 1 · answered May 07 '14 at 20:17

3

You have to write return ++n because return n++ evaluates to the original value of n, and ++n evaluates to the value of n after being incremented.

answered May 07 '14 at 20:17

Pacane

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Or just (n + 1) as anyway the parameter n value is lost once the function returns. So ++n has no long lasting affect here – tgkprog May 07 '14 at 20:19
Why would I delete it? – Pacane May 07 '14 at 20:37

score 1 · Answer 2 · edited May 07 '14 at 20:37

1

Try the following;

public class Return {
    public static void main(String[] args) {
        int n = returnn(3);
        System.out.println(n);
    }

    public static int returnn(int n) {
        return ++n;
    }
}

edited May 07 '14 at 20:37

Anubian Noob

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answered May 07 '14 at 20:16

madteapot

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score 1 · Answer 3 · edited May 07 '14 at 20:36

1

n++ increments n by 1 AFTER evaluating n's current value

++n increments n by 1 and then evaluates its value

Your method returnn(int) should return ++n, instead of n++.

edited May 07 '14 at 20:36

Anubian Noob

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answered May 07 '14 at 20:22

Lucas Oliveira

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Returning Incremented Numbers in Java

3 Answers3