Variable scope and lifetime: Correct Solution

Given the following code:

public class Onhen {
    private static int la = 0;

    public static void main(String[] args) {
        Onhen o0 = new Onhen();
        A
        Onhen o1 = new Onhen();
        o0.ediIoceu(1);
        o1 = o0;
        o1.ediIoceu(10);
        o0.ediIoceu(100);
        o0 = o1;
        o1.ediIoceu(1000);
        B
    }

    private int u = 0;

    public void ediIoceu(int ete) {
        C
        int ime = 0;
        la += ete;
        ime += ete;
        u += ete;
        System.out.println("la=" + la + "  ime=" + ime + "  u=" + u);
    }
}
  1. What does the main method print?
  2. Which of the variables [u, la, ime, o0, o1] are in scope at A ?
  3. Which are in scope at B ?
  4. Which are in scope at C ?

Solution

  1. Output:

    u=1  la=1  ime=1
u=11  la=10  ime=11
u=111  la=100  ime=111
u=1111  la=1000  ime=1111

  2. In scope at A : u, o0, o1

  3. In scope at B : u

  4. In scope at C : u, ime, la

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

  1. u is a static variable, ime is an instance variable, and la is a local variable.

  2. At A , ime is out of scope because it is an instance variable, but main is a static method. la is out of scope because it is local to ediIoceu.

  3. At B , o0 and o1 are out of scope because they are not declared yet. ime is out of scope because it is an instance variable, but main is a static method. la is out of scope because it is local to ediIoceu.

  4. At C , o0 and o1 out of scope because they are local to the main method.

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