Variable scope and lifetime: Correct Solution

Given the following code:

public class Geoosh {
    private int tene = 0;
    private static int pe = 0;

    public static void main(String[] args) {
        A
        Geoosh g0 = new Geoosh();
        Geoosh g1 = new Geoosh();
        B
        g0.largas(1);
        g1.largas(10);
        g0 = g1;
        g0.largas(100);
        g1 = g0;
        g1.largas(1000);
    }

    public void largas(int ti) {
        int pi = 0;
        C
        pi += ti;
        pe += ti;
        tene += ti;
        System.out.println("pi=" + pi + "  pe=" + pe + "  tene=" + tene);
    }
}
  1. What does the main method print?
  2. Which of the variables [tene, pi, pe, g0, g1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    tene=1  pi=1  pe=1
tene=10  pi=11  pe=10
tene=100  pi=111  pe=110
tene=1000  pi=1111  pe=1110

  2. In scope at A : pi, g0

  3. In scope at B : pi, g0, g1

  4. In scope at C : pi, pe, tene

Explanation (which you do not need to write out in your submitted solution):

  1. pi is a static variable, pe is an instance variable, and tene is a local variable.

  2. At A , g1 is out of scope because it is not declared yet. pe is out of scope because it is an instance variable, but main is a static method. tene is out of scope because it is local to largas.

  3. At B , pe is out of scope because it is an instance variable, but main is a static method. tene is out of scope because it is local to largas.

  4. At C , g0 and g1 out of scope because they are local to the main method.

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