Variable scope and lifetime: Correct Solution

Given the following code:

public class StiRisne {
    private int cawe = 0;

    public static void main(String[] args) {
        StiRisne s0 = new StiRisne();
        A
        StiRisne s1 = new StiRisne();
        B
        s0.sedspi(1);
        s1 = s0;
        s0 = new StiRisne();
        s1.sedspi(10);
        s0.sedspi(100);
        s1.sedspi(1000);
    }

    public void sedspi(int iho) {
        int onta = 0;
        ra += iho;
        onta += iho;
        cawe += iho;
        System.out.println("ra=" + ra + "  onta=" + onta + "  cawe=" + cawe);
        C
    }

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

Solution

  1. Output:

    cawe=1  ra=1  onta=1
cawe=11  ra=10  onta=11
cawe=111  ra=100  onta=100
cawe=1111  ra=1000  onta=1011

  2. In scope at A : cawe, s0, s1

  3. In scope at B : cawe, s0, s1

  4. In scope at C : cawe, onta

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

  1. cawe is a static variable, onta is an instance variable, and ra is a local variable.

  2. At A , onta is out of scope because it is an instance variable, but main is a static method. ra is out of scope because it is local to sedspi.

  3. At B , onta is out of scope because it is an instance variable, but main is a static method. ra is out of scope because it is local to sedspi.

  4. At C , ra is out of scope because it is not declared yet. s0 and s1 out of scope because they are local to the main method.

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