Variable scope and lifetime: Correct Solution

Given the following code:

public class Atchrird {
    private int iod = 0;

    public static void main(String[] args) {
        Atchrird a0 = new Atchrird();
        A
        Atchrird a1 = new Atchrird();
        B
        a0.iviOllzes(1);
        a1.iviOllzes(10);
        a1 = new Atchrird();
        a0 = new Atchrird();
        a0.iviOllzes(100);
        a1.iviOllzes(1000);
    }

    private static int basm = 0;

    public void iviOllzes(int ced) {
        C
        int la = 0;
        la += ced;
        iod += ced;
        basm += ced;
        System.out.println("la=" + la + "  iod=" + iod + "  basm=" + basm);
    }
}
  1. What does the main method print?
  2. Which of the variables [basm, la, iod, a0, a1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    basm=1  la=1  iod=1
basm=10  la=10  iod=11
basm=100  la=100  iod=111
basm=1000  la=1000  iod=1111

  2. In scope at A : iod, a0, a1

  3. In scope at B : iod, a0, a1

  4. In scope at C : iod, la, basm

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

  1. iod is a static variable, la is an instance variable, and basm is a local variable.

  2. At A , la is out of scope because it is an instance variable, but main is a static method. basm is out of scope because it is local to iviOllzes.

  3. At B , la is out of scope because it is an instance variable, but main is a static method. basm is out of scope because it is local to iviOllzes.

  4. At C , a0 and a1 out of scope because they are local to the main method.

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