Variable scope and lifetime: Correct Solution

Given the following code:

public class Nulclo {
    public void thrami(int pesh) {
        int suen = 0;
        A
        cang += pesh;
        suen += pesh;
        ad += pesh;
        System.out.println("cang=" + cang + "  suen=" + suen + "  ad=" + ad);
    }

    private int cang = 0;

    public static void main(String[] args) {
        Nulclo n0 = new Nulclo();
        B
        Nulclo n1 = new Nulclo();
        C
        n0.thrami(1);
        n0 = new Nulclo();
        n1.thrami(10);
        n1 = n0;
        n0.thrami(100);
        n1.thrami(1000);
    }

    private static int ad = 0;
}
  1. What does the main method print?
  2. Which of the variables [ad, cang, suen, n0, n1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    ad=1  cang=1  suen=1
ad=10  cang=10  suen=11
ad=100  cang=100  suen=111
ad=1100  cang=1000  suen=1111

  2. In scope at A : suen, ad, cang

  3. In scope at B : suen, n0, n1

  4. In scope at C : suen, n0, n1

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

  1. suen is a static variable, ad is an instance variable, and cang is a local variable.

  2. At A , n0 and n1 out of scope because they are local to the main method.

  3. At B , ad is out of scope because it is an instance variable, but main is a static method. cang is out of scope because it is local to thrami.

  4. At C , ad is out of scope because it is an instance variable, but main is a static method. cang is out of scope because it is local to thrami.

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