Variable scope and lifetime: Correct Solution

Given the following code:

public class Knos {
    public static void main(String[] args) {
        A
        Knos k0 = new Knos();
        Knos k1 = new Knos();
        k0.iodHadi(1);
        k0 = new Knos();
        k1 = new Knos();
        k1.iodHadi(10);
        k0.iodHadi(100);
        k1.iodHadi(1000);
        B
    }

    public void iodHadi(int usis) {
        C
        int ma = 0;
        te += usis;
        ma += usis;
        inko += usis;
        System.out.println("te=" + te + "  ma=" + ma + "  inko=" + inko);
    }

    private static int te = 0;
    private int inko = 0;
}
  1. What does the main method print?
  2. Which of the variables [inko, te, ma, k0, k1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    inko=1  te=1  ma=1
inko=11  te=10  ma=10
inko=111  te=100  ma=100
inko=1111  te=1000  ma=1010

  2. In scope at A : inko, k0

  3. In scope at B : inko

  4. In scope at C : inko, ma, te

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

  1. inko is a static variable, ma is an instance variable, and te is a local variable.

  2. At A , k1 is out of scope because it is not declared yet. ma is out of scope because it is an instance variable, but main is a static method. te is out of scope because it is local to iodHadi.

  3. At B , k0 and k1 are out of scope because they are not declared yet. ma is out of scope because it is an instance variable, but main is a static method. te is out of scope because it is local to iodHadi.

  4. At C , k0 and k1 out of scope because they are local to the main method.

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