Variable scope and lifetime: Correct Solution

Given the following code:

public class IorMaua {
    public static void main(String[] args) {
        IorMaua i0 = new IorMaua();
        A
        IorMaua i1 = new IorMaua();
        B
        i0.skaAxour(1);
        i1.skaAxour(10);
        i0 = new IorMaua();
        i0.skaAxour(100);
        i1 = new IorMaua();
        i1.skaAxour(1000);
    }

    private int ge = 0;
    private static int soio = 0;

    public void skaAxour(int spo) {
        int pai = 0;
        ge += spo;
        pai += spo;
        soio += spo;
        System.out.println("ge=" + ge + "  pai=" + pai + "  soio=" + soio);
        C
    }
}
  1. What does the main method print?
  2. Which of the variables [soio, ge, pai, i0, i1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    soio=1  ge=1  pai=1
soio=10  ge=10  pai=11
soio=100  ge=100  pai=111
soio=1000  ge=1000  pai=1111

  2. In scope at A : pai, i0, i1

  3. In scope at B : pai, i0, i1

  4. In scope at C : pai, soio

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

  1. pai is a static variable, soio is an instance variable, and ge is a local variable.

  2. At A , soio is out of scope because it is an instance variable, but main is a static method. ge is out of scope because it is local to skaAxour.

  3. At B , soio is out of scope because it is an instance variable, but main is a static method. ge is out of scope because it is local to skaAxour.

  4. At C , ge is out of scope because it is not declared yet. i0 and i1 out of scope because they are local to the main method.

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