out of array bounds error

[Iliketofrolic666]

See attached:

the print ln show that the array should be 4 by 3, but
it give an error even when I am trying to set a value at [0][1]

the source code shown is from FSA.java

[Iliketofrolic666]

See attached:

the print ln show that the array should be 4 by 3, but
it give an error even when I am trying to set a value at [0][1]

the source code shown is from FSA.java

import java.io.*;
import java.util.*;

public class FSA{
   private String machineName;      //name of machine
   private int numStates;     	    //number of states
   private String alphabet;         //a list of distinct symbols
   private int[][] transitions;     //numStates-by-length_of_alphabet 
   private String tape;       	    //a string over the alphabet
   private int start;               //start-state
   private boolean[] acceptStates;  //set of accept-states

 
   //Use a Scanner to open the file whose name is fileName.
   //Input the FSA from this file
   public FSA(String fileName) throws IOException
   {
   	   FileReader freader = new FileReader(fileName);
   
   	   Scanner scanner = new Scanner(freader);
   	   
   	   
   	   //Read in file header
   	   machineName = scanner.nextLine();
   	   numStates = scanner.nextInt();
   	   scanner.nextLine();
   	   start = scanner.nextInt();
   	   scanner.nextLine();
   	   alphabet = scanner.nextLine();
   	   
   	   transitions = new int[numStates][alphabet.length()]; 
   	   
   	   System.out.println(alphabet.length()+"     "+numStates);
   	   int i,j,k;
   	   do{
   	   	  i = scanner.nextInt();//state
   	   	  j = scanner.nextInt();//transition
   	   	  k = scanner.nextInt();//new state
   	   	  scanner.nextLine();
   	   	  if (-1 != i )
   	   	  {
   	   	  	  System.out.println("  i: "+i+"  alphabet.charAt():  "+alphabet.charAt(j)+"  j: "+j+"   K:  "+k);
   	   	  	transitions[i][alphabet.charAt(j)] = k;
   	   	  }
   	   	   
   	   } while (-1 != i);
   	   
   	
   	   acceptStates = new boolean[numStates];
   	   for (int temp = 0; temp < numStates; temp++)
   	   {
   	   	   acceptStates[temp] = false;
   	   }
   	   while (scanner.hasNextLine())
   	   {
   	   	   String str = scanner.nextLine();
   	   	   if (-1 != str.indexOf(-1)){break;}
   	   	   for (int temp = 0; temp < numStates; temp++)
   	   	   {
   	   	   	   if (-1 != str.indexOf(temp))
   	   	   	   {
   	   	   	   	   acceptStates[temp] = true;
   	   	   	   }
   	   	   }
   	   }
   	   
   }


   //Display the FSM as show on the next page
   public void displayMachine()
   {
   	  System.out.println("Machine Name: "+machineName);
   	  System.out.print("Set of States: {");
   	  /*for (int i = 0; i < numStates; i++)
   	  {
   	  	  System.out.print(i, 
   	  }*/
   }

   //Return the machineName to caller
   public String name()
   {
   	   return machineName;   
   }

   //Return number of states to caller
   public int numberOfStates()   
   {
   	   return numStates;
   }

   //Return alphabet back to caller
   public String alphabet()
   {   
   	   return alphabet;
   }

   //Return start state back to caller
   public int start()
   {
   	   return start;
   }

   //Return next state if in current state and see symbol
   public int nextState(int current, char symbol)
   {
   	 return transitions[current][alphabet.indexOf(symbol)];   	
   }

   //Return true or false if k is or is or is not a final state.
   public boolean finalState(int k)
   {
   	   return acceptStates[k];
   }

   //Process tape, display transitions and determine if accept or reject tape
   public void processTape(String tape)
   {
   	   
   }
}

[DavidFongs]

If you look at the stack trace, you will see you are out of bounds because you aren't trying to set it at [0][1], you are trying to set it at [0][49]

This is your problem:

transitions[i][alphabet.charAt(j)] = k;

alphabet.charAt(j) returns a character, not an integer. You are using the unicode value of alphabet.charAt(j) which is causing the error