Variable scope and lifetime: Correct Solution

Given the following code:

public class Mocios {
    private int sa = 0;

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

    private static int ress = 0;

    public void bricic(int fle) {
        C
        int nert = 0;
        sa += fle;
        ress += fle;
        nert += fle;
        System.out.println("sa=" + sa + "  ress=" + ress + "  nert=" + nert);
    }
}
  1. What does the main method print?
  2. Which of the variables [nert, sa, ress, m0, m1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    nert=1  sa=1  ress=1
nert=10  sa=11  ress=10
nert=100  sa=111  ress=100
nert=1100  sa=1111  ress=1000

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

  3. In scope at B : sa

  4. In scope at C : sa, nert, ress

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

  1. sa is a static variable, nert is an instance variable, and ress is a local variable.

  2. At A , nert is out of scope because it is an instance variable, but main is a static method. ress is out of scope because it is local to bricic.

  3. At B , m0 and m1 are out of scope because they are not declared yet. nert is out of scope because it is an instance variable, but main is a static method. ress is out of scope because it is local to bricic.

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

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