Variable scope and lifetime: Correct Solution

Given the following code:

public class Stoimgar {
    public void isdar(int nem) {
        A
        int brir = 0;
        brir += nem;
        ble += nem;
        is += nem;
        System.out.println("brir=" + brir + "  ble=" + ble + "  is=" + is);
    }

    public static void main(String[] args) {
        B
        Stoimgar s0 = new Stoimgar();
        Stoimgar s1 = new Stoimgar();
        s0.isdar(1);
        s1.isdar(10);
        s0.isdar(100);
        s0 = new Stoimgar();
        s1 = new Stoimgar();
        s1.isdar(1000);
        C
    }

    private static int ble = 0;
    private int is = 0;
}
  1. What does the main method print?
  2. Which of the variables [is, brir, ble, s0, s1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    is=1  brir=1  ble=1
is=10  brir=11  ble=10
is=100  brir=111  ble=101
is=1000  brir=1111  ble=1000

  2. In scope at A : brir, ble, is

  3. In scope at B : brir, s0

  4. In scope at C : brir

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

  1. brir is a static variable, ble is an instance variable, and is is a local variable.

  2. At A , s0 and s1 out of scope because they are local to the main method.

  3. At B , s1 is out of scope because it is not declared yet. ble is out of scope because it is an instance variable, but main is a static method. is is out of scope because it is local to isdar.

  4. At C , s0 and s1 are out of scope because they are not declared yet. ble is out of scope because it is an instance variable, but main is a static method. is is out of scope because it is local to isdar.

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