JuniorTheoryCommon

What does the program print?

JAVA

public class Main {
    public static void main(String[] args) {
        int[] a = {1, 2, 3};
        int[] b = a;
        int x = a[1];
        b[0] = 9;
        x = 7;
        System.out.println(a[0] + " " + a[1]);
    }
}

9 2

Expecting 1 2: int[] b = a copies only the reference, so a and b lead to one array and b[0] = 9 is seen through a.
Expecting a[1] to become 7: an element of int[] is an int, and int x = a[1] copies its value, not a link to the cell.

How do you make b an independent copy of a?
What happens to the caller's array when a method writes to an element of its array parameter?

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JuniorTheoryCommon

What does the program print?

JAVA

public class Main {
    public static void main(String[] args) {
        int[] a = {1, 2, 3};
        int[] b = a;
        int x = a[1];
        b[0] = 9;
        x = 7;
        System.out.println(a[0] + " " + a[1]);
    }
}

9 2

Expecting 1 2: int[] b = a copies only the reference, so a and b lead to one array and b[0] = 9 is seen through a.
Expecting a[1] to become 7: an element of int[] is an int, and int x = a[1] copies its value, not a link to the cell.

How do you make b an independent copy of a?
What happens to the caller's array when a method writes to an element of its array parameter?

Back to questions Open topic in roadmap →Answer it yourself — Quiz