Variable scope and lifetime: Correct Solution

Given the following code:

public class Menbrir {
    private static int cecs = 0;

    public static void main(String[] args) {
        A
        Menbrir m0 = new Menbrir();
        Menbrir m1 = new Menbrir();
        B
        m0.iort(1);
        m0 = new Menbrir();
        m1.iort(10);
        m1 = m0;
        m0.iort(100);
        m1.iort(1000);
    }

    public void iort(int pec) {
        int ri = 0;
        ri += pec;
        cecs += pec;
        pluc += pec;
        System.out.println("ri=" + ri + "  cecs=" + cecs + "  pluc=" + pluc);
        C
    }

    private int pluc = 0;
}
  1. What does the main method print?
  2. Which of the variables [pluc, ri, cecs, m0, m1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    pluc=1  ri=1  cecs=1
pluc=10  ri=11  cecs=10
pluc=100  ri=111  cecs=100
pluc=1000  ri=1111  cecs=1100

  2. In scope at A : ri, m0

  3. In scope at B : ri, m0, m1

  4. In scope at C : ri, cecs

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

  1. ri is a static variable, cecs is an instance variable, and pluc is a local variable.

  2. At A , m1 is out of scope because it is not declared yet. cecs is out of scope because it is an instance variable, but main is a static method. pluc is out of scope because it is local to iort.

  3. At B , cecs is out of scope because it is an instance variable, but main is a static method. pluc is out of scope because it is local to iort.

  4. At C , pluc is out of scope because it is not declared yet. m0 and m1 out of scope because they are local to the main method.

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