Variable scope and lifetime: Correct Solution

Given the following code:

public class Cessou {
    public void vabe(int gho) {
        int fa = 0;
        A
        jas += gho;
        fa += gho;
        wor += gho;
        System.out.println("jas=" + jas + "  fa=" + fa + "  wor=" + wor);
    }

    public static void main(String[] args) {
        Cessou c0 = new Cessou();
        B
        Cessou c1 = new Cessou();
        C
        c0.vabe(1);
        c0 = new Cessou();
        c1.vabe(10);
        c0.vabe(100);
        c1 = new Cessou();
        c1.vabe(1000);
    }

    private int jas = 0;
    private static int wor = 0;
}
  1. What does the main method print?
  2. Which of the variables [wor, jas, fa, c0, c1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    wor=1  jas=1  fa=1
wor=10  jas=10  fa=11
wor=100  jas=100  fa=111
wor=1000  jas=1000  fa=1111

  2. In scope at A : fa, wor, jas

  3. In scope at B : fa, c0, c1

  4. In scope at C : fa, c0, c1

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

  1. fa is a static variable, wor is an instance variable, and jas is a local variable.

  2. At A , c0 and c1 out of scope because they are local to the main method.

  3. At B , wor is out of scope because it is an instance variable, but main is a static method. jas is out of scope because it is local to vabe.

  4. At C , wor is out of scope because it is an instance variable, but main is a static method. jas is out of scope because it is local to vabe.

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