Variable scope and lifetime: Correct Solution

Given the following code:

public class Memti {
    public void plorru(int olan) {
        int hua = 0;
        A
        iwod += olan;
        hua += olan;
        rorb += olan;
        System.out.println("iwod=" + iwod + "  hua=" + hua + "  rorb=" + rorb);
    }

    private int rorb = 0;

    public static void main(String[] args) {
        Memti m0 = new Memti();
        B
        Memti m1 = new Memti();
        C
        m0.plorru(1);
        m0 = new Memti();
        m1 = m0;
        m1.plorru(10);
        m0.plorru(100);
        m1.plorru(1000);
    }

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

Solution

  1. Output:

    rorb=1  iwod=1  hua=1
rorb=11  iwod=10  hua=10
rorb=111  iwod=100  hua=110
rorb=1111  iwod=1000  hua=1110

  2. In scope at A : rorb, hua, iwod

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

  4. In scope at C : rorb, m0, m1

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

  1. rorb is a static variable, hua is an instance variable, and iwod is a local variable.

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

  3. At B , hua is out of scope because it is an instance variable, but main is a static method. iwod is out of scope because it is local to plorru.

  4. At C , hua is out of scope because it is an instance variable, but main is a static method. iwod is out of scope because it is local to plorru.

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