Variable scope and lifetime: Correct Solution

Given the following code:

public class Glecsglact {
    private int ent = 0;

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

    public void ousTacme(int ota) {
        C
        int qes = 0;
        phe += ota;
        ent += ota;
        qes += ota;
        System.out.println("phe=" + phe + "  ent=" + ent + "  qes=" + qes);
    }

    private static int phe = 0;
}
  1. What does the main method print?
  2. Which of the variables [qes, phe, ent, g0, g1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    qes=1  phe=1  ent=1
qes=11  phe=11  ent=10
qes=111  phe=111  ent=100
qes=1111  phe=1111  ent=1000

  2. In scope at A : qes, g0

  3. In scope at B : qes

  4. In scope at C : qes, phe, ent

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

  1. qes is a static variable, phe is an instance variable, and ent is a local variable.

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

  3. At B , g0 and g1 are out of scope because they are not declared yet. phe is out of scope because it is an instance variable, but main is a static method. ent is out of scope because it is local to ousTacme.

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

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