Thread: Determine source "event" from 2 objects.

I am flipping two coins and the first coin that produces three HEADS in a row wins. The programme should terminate after a coin reaches this goal. And I want to know which coin it was and print a statement saying ie either Coin1 or Coin2 won the race. I can flip them OK and count to three with my two counters headCount1 and headCount2. Problem is I cant pinpoint which coin it was that actually won. Thanks for helping and here is my code:

 
//FlipRace.java
 
public class FlipRace
{
  public static void main (String[] args)
  {
  int headCount1 = 0, headcount2 = 0;
 
  Coin Coin1 = new Coin();
  Coin Coin2 = new Coin();
 
  while (headCount1 < 3 && headCount2 < 3) 
  {
    Coin1.flip();
    Coin2.flip();
    System.out.println ("Coin1: " + Coin1);
    System.out.println ("Coin2: " + Coin2);
    if (Coin1.isHeads())
        headCount1++;
    if (Coin2.isHeads())
        headCount2++;
   }  
 
  System.out.println ("A headCount attained 3. (Coin was flipped" + 
  " heads 3 times in a row.");
 
  }
}

And the main class:

 
//Coin.java
//Represents a coin with two sides that can be flipped.
 
public class Coin
{
  private final int HEADS = 0;
  private final int TAILS = 1;
 
  private int face;
 
  //sets up the coin by flipping it initially.
  public Coin ()
  {
    flip();
  }
 
  //flips the coin by randomly choosing a face value.
  public void flip ()
  {
    face = (int) (Math.random() * 2);
  }
 
  //returns true if the current face of the coin is heads.
  public boolean isHeads ()
  {
    return (face == HEADS);
  }
 
  //returns the current face of the coin as a string.
  public String toString()
  {
    String faceName;
 
    if (face == HEADS)
        faceName = "Heads";
    else
        faceName = "Tails";
 
    return faceName;
  }
}

Java is case sensitive (as are Java programmers). headCount2 != headcount2.

Fixing that problem should answer your question, but let us know if you need more help.

Edit: No, maybe not. Your logic is not right. You want to keep track of heads flipped but if a tail is flipped, then zero the headsFlipped count. Your current logic simply waits for 3 heads whether they're in a row or not. Rework the logic as I've suggested.

BTW: If you have errors, you should post them, exactly as they appear at your end, copied and pasted.

Well I got there. I printed the state of each headCount object at the bottom of the code. And it shows me which one attained 3 and which one didnt. I am happy with that too, I just wonder is there a smarter way of doing it?

//FlipRace.java
 
public class FlipRace
{
  public static void main (String[] args)
  {
  int headCount1 = 0, headCount2 = 0;
 
  Coin Coin1 = new Coin();
  Coin Coin2 = new Coin();
 
  while (headCount1 < 3 && headCount2 < 3) 
  {
    Coin1.flip();
    Coin2.flip();
    System.out.println ("Coin1: " + Coin1);
    System.out.println ("Coin2: " + Coin2);
    System.out.println(); 
    if (Coin1.isHeads())
        headCount1++;
    else
        headCount1 = 0;
    if (Coin2.isHeads())
        headCount2++;
    else
        headCount2 = 0;
  }  
  System.out.println (headCount1);
  System.out.println (headCount2);
  }
}

Originally Posted by Junky

You could use an if statement: if coin1 has 3 heads print coin one wins else print coin two wins. Up for debate: should headCount be a instance variable of Coin?

I think I know what your saying. I should write a method in the Coin class, something like public void headCount () and declare headCount as a variable?
How do I write a method in the Coin class to determine the value of the headCount? My if else statements that calculate it are in the FlipRace class ...