Comparing array entries in Java

Question

I am writing a program to determine the winner of a race between a tortoise, hare, wolf, and sheep. The race is divided into 10 time steps (0-9). Each participant moves at a different rate. I need to output the total distance traveled by each party and declare a winner, and if there is a tie I can choose any of the tied parties to output as the winner.

My problem is coming from the part where I declare the Array "array" and use if else if to determine the winner. The error message I'm getting is saying the variable "winner" has not been initialized. I assume this is because I'm not comparing the array entries correctly and none of the if statements are returning a true value. My goal was to sort the array into ascending order, then take the highest value (the farthest distance traveled) and figure out which variable it is represented by (hare, tortoise, sheep, wolf) by using the == operator. What am I doing wrong?

import java.util.*;

public class Hw3pr5 {
  public static void main(String[] args) {
    double hare = 0, tortoise = 0; //these variables will hold the total
    double sheep = 0, wolf = 0; //distance covered by each racer
    String winner;

    for (int index = 0; index < 10; index++) {
      hare = hareTimeStep(index, hare);
      tortoise = tortoiseTimeStep(index, tortoise);
      sheep = sheepTimeStep(index, sheep);
      wolf = wolfTimeStep(index, wolf);
    }

    double[] array = {
      hare, tortoise, sheep, wolf
    };
    Arrays.sort(array);
    if (array[0] == hare)
      winner = "hare";
    else if (array[0] == tortoise)
      winner = "tortoise";
    else if (array[0] == sheep)
      winner = "sheep";
    else if (array[0] == wolf)
      winner = "wolf";

    System.out.println("The race is over. The hare traveled " + hare +
      " miles.\nThe tortoise traveled " + tortoise +
      " miles.\nThe sheep traveled " + sheep + " miles.\nThe " +
      "wolf traveled " + wolf + " miles.\nThe grand winner: the " +
      winner + "!");

  }

  public static double hareTimeStep(int timestep, double distance) {
    Random rnd = new Random();
    double progress = 0;

    if (timestep < 2)
      progress = 13 + rnd.nextDouble() * 4;
    distance += progress;
    return distance;
  }

  public static double tortoiseTimeStep(int timestep, double distance) {
    Random rnd = new Random();
    double progress = 2 + rnd.nextDouble() + rnd.nextDouble();
    distance += progress;
    return distance;
  }

  public static double sheepTimeStep(int timestep, double distance) {
    Random rnd = new Random();
    double progress = 0;
    if (timestep % 2 == 0)
      progress = 6 + 4 * rnd.nextDouble();
    else
      progress -= 2;
    distance += progress;
    return distance;
  }

  public static double wolfTimeStep(int timestep, double distance) {
    Random rnd = new Random();
    double progress;

    if (timestep % 3 == 0)
      progress = 0;
    else
      progress = 4 + rnd.nextDouble();

    distance += progress;
    return distance;
  }
}

Change String winner; to String winner = "";, but I wonder if you have more severe problems. What if hare == tortoise? Who is the winner? — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Mar 8, 2015 at 3:11
I can tell you that the compiler is complaining about the winner variable because it may not get initialized in your code, depending on what the value of array[0] is. — Tim Biegeleisen
– Tim Biegeleisen, Commented Mar 8, 2015 at 3:14
If hare = tortoise, the first if statement should return true and winner would be set to "hare", correct? — Tommy
– Tommy, Commented Mar 8, 2015 at 3:16

Aify · Accepted Answer · 2015-03-08 03:26:16Z

1

The problem is that you're using a bunch of if-else statements with no ending else block.

Basically, you need to give winner a default value, because in your current code, if array[0] doesn't match anything, winner will never be set.

Or, you can append an else block to your code which will initialize winner.

Another solution: change the very last block of your if-else to else. This makes the last case the default case.

eg:

 String winner = "default"; // this can be anything you want as long as it's not null

or

if (array[0] == hare)
  winner = "hare";
else if (array[0] == tortoise)
  winner = "tortoise";
else if (array[0] == sheep)
  winner = "sheep";
else if (array[0] == wolf)
  winner = "wolf";
else winner = "default case"

or

if (array[0] == hare)
  winner = "hare";
else if (array[0] == tortoise)
  winner = "tortoise";
else if (array[0] == sheep)
  winner = "sheep";
else winner = "wolf"; 
// the logic still works here - if it wasn't the hare, tortoise or sheep it must be the wolf

edited Mar 8, 2015 at 3:26

answered Mar 8, 2015 at 3:14

Aify

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1 Comment

Tommy Over a year ago

Thank you so much, I initialized String winner = ""; at the very beginning, then I also realized that I misunderstood what ascending order meant in the Arrays.sort method - I changed the array index in the if else if block to 3, changed the last else if to an else, and it works perfectly now!

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