JuniorTheoryCommon

What does the program print?

JAVA

public class Main {
    public static void main(String[] args) {
        Point p = new Point();
        p.x = 1;
        Point q = p;
        q.x = 7;
        q = new Point();
        q.x = 9;
        System.out.println(p.x);
    }
}
class Point { int x; }

Expecting 1: Point q = p copies only the reference, so p and q lead to one object and q.x = 7 is seen through p.
Expecting 9: q = new Point() makes only q lead to a new object; p keeps the old one, where x is still 7.

How would you make q an independent copy of the point p?
What would p == q print right after Point q = p?

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JuniorTheoryCommon

What does the program print?

JAVA

public class Main {
    public static void main(String[] args) {
        Point p = new Point();
        p.x = 1;
        Point q = p;
        q.x = 7;
        q = new Point();
        q.x = 9;
        System.out.println(p.x);
    }
}
class Point { int x; }

Expecting 1: Point q = p copies only the reference, so p and q lead to one object and q.x = 7 is seen through p.
Expecting 9: q = new Point() makes only q lead to a new object; p keeps the old one, where x is still 7.

How would you make q an independent copy of the point p?
What would p == q print right after Point q = p?

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