/* 
 * Foo.java
 * Illustration of a program with two classes.
 * This must be compiled together with Bar.java: javac Foo.java Bar.java
 */

public class Foo
  {
  // Example of a static or class variable.
  private static int numberOfFoos = 0;

  // Instance variables.
  private int fooID; // ID number of an instance.
  private Bar fooBar; // Illustrate use of another class.

  // Constructor.
  public Foo(int id)
    {
    numberOfFoos++; // Count the new instance we are creating.
    fooID = id;
    fooBar = new Bar(id);
    }

  // Static method to access a static variable.
  public static void printFooCount()
    {
    System.out.println("The number of Foos is " + numberOfFoos);
    }

  // Static method to print out a number of foos.
  public static void printSomeFoos(int n)
    {
    for (int i = 1; i <= n; i++)
      {
      System.out.print("foo ");
      }
    System.out.println();
    }

  // Instance method to access an instance variable.
  public void printFooID()
    {
    System.out.println("The ID of this foo is " + fooID);
    }

  // Main method to demo this class. 
  public static void main(String[] args)
    {
    printSomeFoos(5);
    System.out.println("Before:");
    printFooCount();
    Foo foo1 = new Foo(10);
    Foo foo2 = new Foo(20);
    System.out.println("After:");
    printFooCount();
    foo1.printFooID();
    foo1.fooBar.printBarID();
    foo2.printFooID();
    foo2.fooBar.printBarID();
    }
  }