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Thread: Re: null pointer exception problem

  1. #1
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    Default Re: null pointer exception problem

    hey im having the same problem with my code im a beginner in a programing class and have been trying to figure it out for days im trying to build a game of hangman.
    class TestGuessList
    {
      private char guessList;
      public static void main (String []args)
      {
        GetInput input = new GetInput();
        GuessList list = new GuessList();
        char guessList = ' ';
        int turns=5;
     
        for (int f=0;f<5;f++)
        {
          boolean done = false;
          System.out.println("You have " + turns + " turns remaining ");
          while (done == false)
          {
            input.setUserInput();
            guessList=input.getUserInput();
            while (list.inGuessList(guessList)==true)
            {
            System.out.println("This letter has already been guessed");
            }
            done = false;
          }
           turns--;      
          System.out.print("the letters that you have already guessed and added to you ignore list are: ");
          list.print();
          System.out.println("\n");
        }
      }
    }
     
    the method class is this
     
    public class GuessList// Class is responsible for insuring the letter guess is valid.
    {
      private char[] list; //Creates a private array character variable called list.
        public GuessList()// Creates a public method called GuessList.
        {
          char[] list = new char [0];//Creates an array called list.
        }
       public boolean inGuessList(char c)//Creates a public boolean method called inGuessList.
        {
         boolean duplicate=false;//Creates a boolean called duplicate and sets it to false.
          for(int x=0; x<list.length;x++)/*Creates a for loop with int x and sets it less then the length of 
           * list and not equal to duplicate.*/
         {
          if(list[x] == c )// Ifs statement for if list is equal to c.
          {
            duplicate = true;//Makes duplicate true.
            return duplicate;//Returns duplicate.
          }
          }
          return false;
        }
     
        public void print()//Print method.
        {
          System.out.println("The letters you have guessed are ");//Prints the letters guessed to the user.
          for(int i = 0;i<list.length;i++)//Creates a for loop for int i.
          {
            System.out.println(list[i] + " ");//Prints list[i].
          }
        }
        char[] getGuessList()//Creates an array method.
        {
          return list;//Returns the list.
        }
        public void addToGuessList(char guesses)//Creates a method called addToGuessList.
        {
          char[] list2 = new char [list.length +1];//Creates a second longer array.
          for(int t = 0; t<list.length; t++)//Creates a for loop less the the size of list.
          {
            list2[t]=list[t];//Makes list2[t] equal to list[t].
          }
          list2[list.length] = guesses;//Makes list2[list.length] equal to guesses.
          list=list2;//Makes list equal to list2.
        }    
        }
    please help..
    Last edited by copeg; April 2nd, 2011 at 08:55 PM.


  2. #2
    Administrator copeg's Avatar
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    Default Re: null pointer exception problem

    First, please don't hijack someone else's post - I've moved this to its own thread. Second, in the future please use the code tags - makes the source code readable. Lastly, you've posted a bit of code - I recommend posting the exception stack trace which helps pinpoint the problem.

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