Variable scope and lifetime: Correct Solution

Given the following code:

public class Peadfles {
    public void oesm(int he) {
        int pini = 0;
        A
        goc += he;
        ced += he;
        pini += he;
        System.out.println("goc=" + goc + "  ced=" + ced + "  pini=" + pini);
    }

    private static int ced = 0;
    private int goc = 0;

    public static void main(String[] args) {
        Peadfles p0 = new Peadfles();
        B
        Peadfles p1 = new Peadfles();
        C
        p0.oesm(1);
        p1.oesm(10);
        p0 = p1;
        p1 = new Peadfles();
        p0.oesm(100);
        p1.oesm(1000);
    }
}
  1. What does the main method print?
  2. Which of the variables [pini, goc, ced, p0, p1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    pini=1  goc=1  ced=1
pini=10  goc=11  ced=10
pini=110  goc=111  ced=100
pini=1000  goc=1111  ced=1000

  2. In scope at A : goc, pini, ced

  3. In scope at B : goc, p0, p1

  4. In scope at C : goc, p0, p1

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

  1. goc is a static variable, pini is an instance variable, and ced is a local variable.

  2. At A , p0 and p1 out of scope because they are local to the main method.

  3. At B , pini is out of scope because it is an instance variable, but main is a static method. ced is out of scope because it is local to oesm.

  4. At C , pini is out of scope because it is an instance variable, but main is a static method. ced is out of scope because it is local to oesm.

Related puzzles: