Variable scope and lifetime: Correct Solution

Given the following code:

public class Rhilru {
    private int emo = 0;
    private static int pse = 0;

    public void oucEsqeck(int feci) {
        A
        int ir = 0;
        emo += feci;
        pse += feci;
        ir += feci;
        System.out.println("emo=" + emo + "  pse=" + pse + "  ir=" + ir);
    }

    public static void main(String[] args) {
        B
        Rhilru r0 = new Rhilru();
        Rhilru r1 = new Rhilru();
        C
        r0.oucEsqeck(1);
        r1.oucEsqeck(10);
        r0 = new Rhilru();
        r1 = r0;
        r0.oucEsqeck(100);
        r1.oucEsqeck(1000);
    }
}
  1. What does the main method print?
  2. Which of the variables [ir, emo, pse, r0, r1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    ir=1  emo=1  pse=1
ir=10  emo=11  pse=10
ir=100  emo=111  pse=100
ir=1100  emo=1111  pse=1000

  2. In scope at A : emo, ir, pse

  3. In scope at B : emo, r0

  4. In scope at C : emo, r0, r1

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

  1. emo is a static variable, ir is an instance variable, and pse is a local variable.

  2. At A , r0 and r1 out of scope because they are local to the main method.

  3. At B , r1 is out of scope because it is not declared yet. ir is out of scope because it is an instance variable, but main is a static method. pse is out of scope because it is local to oucEsqeck.

  4. At C , ir is out of scope because it is an instance variable, but main is a static method. pse is out of scope because it is local to oucEsqeck.

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