JuniorTheoryCommon

What does the program print?

JAVA

public class Main {
    public static void main(String[] args) {
        Counter a = new Counter();
        new Counter();
        System.out.println(Counter.count + " " + a.id);
    }
}
class Counter {
    static int count;
    int id;
    Counter() { id = ++count; }
}

2 1

Expecting 1 1: a static field is one for the whole class, so each new adds to the same count, and it reaches 2.
Expecting 2 2: id = ++count copies the current value into the object once; later changes of count do not reach a.id.

Why can a static method read count but not id?
What happens to this program if count is declared without static?

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Back to questions

JuniorTheoryCommon

What does the program print?

JAVA

public class Main {
    public static void main(String[] args) {
        Counter a = new Counter();
        new Counter();
        System.out.println(Counter.count + " " + a.id);
    }
}
class Counter {
    static int count;
    int id;
    Counter() { id = ++count; }
}

2 1

Expecting 1 1: a static field is one for the whole class, so each new adds to the same count, and it reaches 2.
Expecting 2 2: id = ++count copies the current value into the object once; later changes of count do not reach a.id.

Why can a static method read count but not id?
What happens to this program if count is declared without static?

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