Variable scope and lifetime: Correct Solution

Given the following code:

public class Icioc {
    private static int arci = 0;
    private int pa = 0;

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

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

Solution

  1. Output:

    ce=1  arci=1  pa=1
ce=11  arci=10  pa=10
ce=111  arci=110  pa=100
ce=1111  arci=1000  pa=1000

  2. In scope at A : ce, i0

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

  4. In scope at C : ce, arci, pa

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

  1. ce is a static variable, arci is an instance variable, and pa is a local variable.

  2. At A , i1 is out of scope because it is not declared yet. arci is out of scope because it is an instance variable, but main is a static method. pa is out of scope because it is local to saeas.

  3. At B , arci is out of scope because it is an instance variable, but main is a static method. pa is out of scope because it is local to saeas.

  4. At C , i0 and i1 out of scope because they are local to the main method.

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