Variable scope and lifetime: Correct Solution

Given the following code:

public class Meuc {
    private static int ozi = 0;

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

    public void clis(int as) {
        int o = 0;
        C
        ozi += as;
        rast += as;
        o += as;
        System.out.println("ozi=" + ozi + "  rast=" + rast + "  o=" + o);
    }

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

Solution

  1. Output:

    o=1  ozi=1  rast=1
o=11  ozi=10  rast=10
o=111  ozi=101  rast=100
o=1111  ozi=1010  rast=1000

  2. In scope at A : o, m0, m1

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

  4. In scope at C : o, ozi, rast

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

  1. o is a static variable, ozi is an instance variable, and rast is a local variable.

  2. At A , ozi is out of scope because it is an instance variable, but main is a static method. rast is out of scope because it is local to clis.

  3. At B , ozi is out of scope because it is an instance variable, but main is a static method. rast is out of scope because it is local to clis.

  4. At C , m0 and m1 out of scope because they are local to the main method.

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