Variable scope and lifetime: Correct Solution

Given the following code:

public class Lecuc {
    private int ri = 0;

    public void ropli(int me) {
        A
        int xel = 0;
        coph += me;
        xel += me;
        ri += me;
        System.out.println("coph=" + coph + "  xel=" + xel + "  ri=" + ri);
    }

    public static void main(String[] args) {
        Lecuc l0 = new Lecuc();
        B
        Lecuc l1 = new Lecuc();
        l0.ropli(1);
        l1 = l0;
        l1.ropli(10);
        l0 = l1;
        l0.ropli(100);
        l1.ropli(1000);
        C
    }

    private static int coph = 0;
}
  1. What does the main method print?
  2. Which of the variables [ri, coph, xel, l0, l1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    ri=1  coph=1  xel=1
ri=11  coph=10  xel=11
ri=111  coph=100  xel=111
ri=1111  coph=1000  xel=1111

  2. In scope at A : ri, xel, coph

  3. In scope at B : ri, l0, l1

  4. In scope at C : ri

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

  1. ri is a static variable, xel is an instance variable, and coph is a local variable.

  2. At A , l0 and l1 out of scope because they are local to the main method.

  3. At B , xel is out of scope because it is an instance variable, but main is a static method. coph is out of scope because it is local to ropli.

  4. At C , l0 and l1 are out of scope because they are not declared yet. xel is out of scope because it is an instance variable, but main is a static method. coph is out of scope because it is local to ropli.

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