Variable scope and lifetime: Correct Solution

Given the following code:

public class Feancass {
    private static int iss = 0;

    public void krelci(int slo) {
        A
        int snev = 0;
        po += slo;
        iss += slo;
        snev += slo;
        System.out.println("po=" + po + "  iss=" + iss + "  snev=" + snev);
    }

    private int po = 0;

    public static void main(String[] args) {
        Feancass f0 = new Feancass();
        B
        Feancass f1 = new Feancass();
        C
        f0.krelci(1);
        f0 = new Feancass();
        f1.krelci(10);
        f0.krelci(100);
        f1 = new Feancass();
        f1.krelci(1000);
    }
}
  1. What does the main method print?
  2. Which of the variables [snev, po, iss, f0, f1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    snev=1  po=1  iss=1
snev=10  po=11  iss=10
snev=100  po=111  iss=100
snev=1000  po=1111  iss=1000

  2. In scope at A : po, snev, iss

  3. In scope at B : po, f0, f1

  4. In scope at C : po, f0, f1

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

  1. po is a static variable, snev is an instance variable, and iss is a local variable.

  2. At A , f0 and f1 out of scope because they are local to the main method.

  3. At B , snev is out of scope because it is an instance variable, but main is a static method. iss is out of scope because it is local to krelci.

  4. At C , snev is out of scope because it is an instance variable, but main is a static method. iss is out of scope because it is local to krelci.

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