Programming Forums - Problem With Arrays

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- - Problem With Arrays (http://www.programmingforums.org/showthread.php?t=1109)

My problem is that I want to be able to create an array, but instead of entering the array by hand, I want for it to be read in from a text file, a string token at a time. I then want to sort it, I have looked at using a selction sort etc, and read up on the java.util.Arrays.sort method, and just cant make it work.

My code is as follows:

import java.util.*;

import java.io.*;

public class Example

{

  public static void main() throws IOException

  {

    //set up input stream

    BufferedReader filein = new BufferedReader(new FileReader("C:\\Program Files\\filein.txt"));

 //set up output stream

   PrintWriter fileout = new PrintWriter(new FileWriter("C:\\Program Files\\fileout.txt"));



    

    //Declare variables

    String nextLine; //a line read from file

    StringTokenizer t; //the words within the line

    ArrayList a = new ArrayList(); //store all words here 

    String s; //next word

    boolean isAWord; //true if string represents a Word     

    char[] nVal = { '.',',','!',':',';','?' }; // not valid characters

    int countGood=0, countBad=0;  

    

    System.out.println("Starting to read");

    nextLine = filein.readLine();   //read from input file

    //start         

    while (nextLine != null)

    {

      t = new StringTokenizer(nextLine); //identify words

      nextLine = nextLine.toLowerCase( );//Converts to Lowercase()

          

      while (t.hasMoreTokens())

      {    

        a.add(t.nextToken()); //add next word to list                                        

      }        

    

    java.util.Arrays.sort(a);

    // This line wont work and brings up the error that it cannot resolve symbol

    } //finished reading file

    

    fileout.println(a);

    

    System.out.println("Finished");

    fileout.close();

    

  }

}

I have a problem getting anything to be written to the fileout textfile, and my sort method again doesnt seem to work. Could anybody help me out please?

Thanks

Andy

I made a few small changes to your program. I changed it first to a do-while loop, because it has to go through at least once. I also put your readline inside the loop. Then, your sort method was giving me some errors, so I used a sort method inside the collectinos class. Just changed three lines, basically. Here's your edited code.

import java.util.*;

import java.io.*;

public class Example2

{

  public static void main() throws IOException

  {

    //set up input stream

    BufferedReader filein = new BufferedReader(new FileReader("filein.txt"));

 //set up output stream

  PrintWriter fileout = new PrintWriter(new FileWriter("fileout.txt"));



   

    //Declare variables

    String nextLine; //a line read from file

    StringTokenizer t; //the words within the line

    ArrayList a = new ArrayList(); //store all words here

    String s; //next word

    boolean isAWord; //true if string represents a Word    

    char[] nVal = { '.',',','!',':',';','?' }; // not valid characters

    int countGood=0, countBad=0; 

    

    System.out.println("Starting to read");

    

    //start        

    do

    {

  nextLine = filein.readLine();   //read from input file    

      t = new StringTokenizer(nextLine); //identify words

      nextLine = nextLine.toLowerCase( );//Converts to Lowercase()

          

      while (t.hasMoreTokens())

      {   

        a.add(t.nextToken()); //add next word to list                                       

      }       

    

    Collections.sort(a);

    // This line wont work and brings up the error that it cannot resolve symbol

    

    }while (nextLine != null); //finished reading file

    

    fileout.println(a);

    

    System.out.println("Finished");

    fileout.close();

   

  }

}

Hi, me and a couple of my freinds got together and have managed to come up with some different code. My question is whether there is any possible way at all to make this code more efficient, even if it is just making a snipet of the code shorter, or getting rid of a line here and there. You see we get marked on efficiency for this you see, and I also think my structure is not the best, if you have any suggestions how to make it better?

Thyanks



import java.util.*;

import java.io.*;

  

public class Example2

{

  public static void main(String [] args) throws IOException

  {

    

      

    //set up input stream

    File finput = new File("C:\\fi.txt");

    FileReader fread = new FileReader(finput);

    BufferedReader fin = new BufferedReader(fread);



    String nextLine; //a line read from file 

    StringTokenizer t; //the words within the line

    ArrayList words = new ArrayList(); // store all words here

    String tmpString;         

    int identification;

    

    System.out.println("\nGo through text\n"); 

    

    while (true)  //potentially infinite loop

    {

      nextLine = fin.readLine();      //read from input file

      if (nextLine == null) break;    //if no more lines, get out

      t = new StringTokenizer(nextLine);  //identify words

      while (t.hasMoreTokens()) 

      {

        tmpString=t.nextToken();



        //invoke a method for identify if it is a word

        identification=isWord(tmpString); 

        

        switch(identification)

        {

           case -3:   // it is a word

           {

            tmpString=tmpString.toLowerCase(); //convert to lowercases

            words.add(tmpString);        //add into arraylist

            break;

           }

           

           case -1:   

           break;   //it is not a word, so do nothig;

           

           case -2:  // it is a word with end of punctuation;

           {

             //eliminate punctuations;

tmpString=tmpString.substring(0,tmpString.length()-1);



            words.add(tmpString.toLowerCase()); //add into arraylist;   

            break;

           }

         }//end of switch

         

        

      }// end of internal while

    } //end of external while

    

    // Begin to sort...

    

//invoke a method to sort ArrayList words in an dictionary order

    toSort(words); 

    //invoke a method to output the result into a file and display on screen

printResult(words);

     

    fin.close(); //close the input dream

    System.out.println("\nFinished!");   

    }// end of method main()

    

 

  public static void toSort(ArrayList forSorting)

  {

    System.out.println("\nStarting to sort....");

    int arraySize=forSorting.size();

    String x; //temp swapping variable

    int j; 

    

    //sorting the arraylist with InsertionSort algorithm

    for(int i=0;i<arraySize;i++)

    {  

      x=(String) forSorting.get(i); //element to be inserted

      for(j=i;j>0 && x.compareTo(((String)forSorting.get(j-1)))<0;j--) 

      {

        forSorting.set(j,forSorting.get(j-1));

      }

      forSorting.set(j,x);

       

    }//end of for loop

  

}//end of method toSort()







public static int isWord(String ifWord)

 

  {

    String alphaCaps = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    String alphaLower = alphaCaps.toLowerCase();

    String allowable = alphaCaps + alphaLower; //the string of valid letters

    String allowPunc=",;:.!?";  // the string of valid punctuations 

       

    //Starting to identify�..



    if (allowable.indexOf(ifWord.charAt(0))==-1) //check the first char 

    {

      return -1; // if first char is not a letter, the token is not a word

    } 

    

    else // check the rest of the token

    {

      

      for(int i=1;i<ifWord.length();i++)

      {

        if (allowable.indexOf(ifWord.charAt(i))==-1)

        {

          //identify if the last second letter is a punctuation 

if (i<ifWord.length( )-1)

            return -1;   // it is not a word.



          //identify if the last letter is a punctuation

          //if yes, identify whether it is a valid punctuation.

          if (i==ifWord.length( )-1 && allowPunc.indexOf(ifWord.charAt(i))!=-1)

            return -2;   // it is a word with end of punctuation

else

            return -1;  // String with unallowable punctuation

         }

      } // end of for loop

     }// end of external if statement

      

     return -3; // it is a word.

     

  } //end of method isWord()   





public static void printResult(ArrayList result) throws IOException

  {

    //set up output stream

    File foutput = new File("C://fo.txt");

    FileWriter fwrite = new FileWriter(foutput);

    PrintWriter fout = new PrintWriter(fwrite);

        

    System.out.println("\nStarting to output the result:"+"\n");

    

    int counter=1; //initialize the appear times

    int j;

    

    for(int i=0;i<result.size();i++)

    {

       j=i+1;

       if( j<=result.size()-1 && ((String) result.get(i)).compareTo((String) result.get(j))==0)

       {

        counter++;

       }

       else

       {

       //Starting to output

        if (((String) result.get(i)).length()>=8) 

        {

          System.out.println(result.get(i)+"\t\t"+counter);

          fout.println(result.get(i)+"\t\t"+counter);

         }

         else

         {

          System.out.println(result.get(i)+"\t\t\t"+counter );

          fout.println(result.get(i)+"\t\t\t"+counter);

         }

         

       counter=1; //back the counter to 1 for the next word

      

       }

 

    }//end of for loop

    

    fout.close(); //close the output stream

    

  }//end of method method printResult()

   

  

}//end of the class

Thanks mate

Sco