Head First Java- Simple Dot Com Game help

[John Pisci]

Hi everyone, hope you can help.

Firstly, apologies for attaching all of the code and the length of the post!

I'm struggling to make the following compile and I am unsure why as I have checked my code against the code given in the book and can't see any problems.
The errors I get are:
illegal initializer for int
int locations = {randomNum, randomNum+1, randomNum+2};
and
setLocationCells(int[]) in SimpleDotCom cannot be applied to an (int)
theDotCom.setLocations(locations);

public class UpdatedSimpleDotCom
{
  public static void main(String[] args)
  {
    int numOfGuesses = 0;
    GameHelper helper = new GameHelper();
    SimpleDotCom theDotCom = new SimpleDotCom();
 
    /* The Math.random command outputs as a double and produces a number
       between 0 and 0.9. Casting as an int cuts off the decimal and
       multiplying by 5 gives a number between 0 and 4. */
    int randomNum = (int) (Math.random() * 5);
    
    //Sets an array for the DotCom object, sets 3 consecutive cells.
    int locations = {randomNum, randomNum+1, randomNum+2};
    theDotCom.setLocationCells(locations);
    boolean isAlive = true;
    
    while (isAlive == true)
    {
      String guess = helper.getUserInput("Enter a Number");
      String result = theDotCom.checkYourself(guess);
      numOfGuesses++;
      
      if (result.equals ("Kill!"))
      {
        isAlive = false;
        System.out.println("You took " + numOfGuesses + " guesses");
      }
    }
  }
}    

import java.io.*;
 
public class GameHelper
{
  public String getUserInput(String prompt)
  {
    String inputLine = null;
    System.out.print(prompt + " ");
    
    try
    {
      BufferedReader is = new BufferedReader(new InputStreamReader(System.in));
      inputLine = is.readLine();
      
      if (inputLine.length() == 0) return null;
    }
    catch (IOException e)
    {
      System.out.println("IOException " + e);
    }
    return inputLine;
  }
}    

public class SimpleDotCom
{
  int[] locationCell;
  int numOfHits = 0;
  
  public void setLocationCells(int[] locs)
  {
    locationCell = locs;
  }
  
  public String checkYourself (String stringGuess)
  {
    // Converts an int to a String
    int guess = Integer.parseInt(stringGuess);
    String result = "You're shit! MISS!";
    
    // Repeat for each location cell populated
    for (int cell : locationCell)
    {
      if (guess == cell)
      {
        result = "Hit!";
        numOfHits++; // Increase numOfHits by 1
        break; // Gets you out of the loop
      }
    }
    // Does numOfHits = the number of cells taken up by the target
    if (numOfHits == locationCell.length)
    {
      result = "Kill!";
    }
    System.out.println(result);
    return result;
  }  
}    

[edit]Change a // comment to /* */ to fit everything into screen width. CR[/edit]
[ December 19, 2008: Message edited by: Campbell Ritchie ]

[Henry Wong]

int locations = {randomNum, randomNum+1, randomNum+2};

The locations variable is declared as an int, it can't be assigned an int array. To do that you need to declare "locations" as an int array.

setLocationCells(int[]) in SimpleDotCom cannot be applied to an (int)
theDotCom.setLocations(locations);

The setLocationCells() method takes an int array. You can't pass it a regular int. If "locations" had been declared as an int array, as suggested as a possible fix to the previous error, then this error gets fixed too.

Henry

[John Pisci]

Henry, you are a star!

Although, once I had added the [], I compared my code to the code in the book (for what seems like the 100th time!) and the brackets were there all along!

Thanks again!

[Campbell Ritchie]

Welcome to JavaRanch

The comment I changed doesn't quite describe what you are doing.
You say "casting to int and multiplying by 5" which would give 0 in all instances.
What you are doing is "multiplying by 5 and casting to an int" which is actually correct. Math.random() actually returns a number between 0 and 0.9999999..... inclusive.

If you go through the methods of the Random class you can find an alternative way to get a (pseudo)random number between 0 and 4.