Question

In my program, it reads a file called datafile.txt… inside the datafile.txt is a random 3 lines of words. What my program does is reads the file the user types in and then they can type in a Line # and Word # and it will tell them the word that is in that location.. for example..

What is the file to read from?

datafile.txt

Please enter the line number and word number (the first line is 1).

2 2

The word is: the

My problem is that my program reads the 3 lines in the txt doc as 0, 1 ,2 and the words start from 0. So to read the first word in the first line they would have to type 0,0 instead of 1,1. What I am trying to do is make it work so they can type 1,1 instead of 0,0. Not sure what my problem is right now, here is my code….

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class readingFile {

    /**
    * @param args
    * @throws IOException 
    * @throws validException 
    */
    public static void main(String[] args) throws IOException, checkException 
    {
        System.out.println("Enter file name: " );
        Scanner keyboard = new Scanner(System.in);
        BufferedReader inputStream = null;
        ArrayList<String> file = new ArrayList<String>();
        String fileName = keyboard.next();
        System.out.println ("The file " + fileName +
                " has the following lines below: ");
        System.out.println();

        try
        {
            inputStream = new BufferedReader(new FileReader(fileName));         
            ArrayList<String> lines = new ArrayList<String>();
            while(true)
            {
                String line = inputStream.readLine();
                if(line ==null)
                {
                    break;
                }

                Scanner itemnize = new Scanner(line);
                while(itemnize.hasNext())
                {
                    lines.add(itemnize.next());
                }
                lines.addAll(lines);

                System.out.println(lines+"\n");                 
            }       

            System.out.println("Please enter the line number and word number");

            int index1 = keyboard.nextInt();
            int index = keyboard.nextInt();

            System.out.println("The word is: "+ lines.get(index));
        }
        catch(FileNotFoundException e)
        {
            System.out.println("Error opening the file " + fileName);
        }
        inputStream.close();
    }

    private static void checkValid(ArrayList<String> items, int index) throws checkException
    {
        throw new checkException("Not Found");
    }       
} 

Answer 1

As I assume you are just learning to program I will point out 3 areas of improvement

• Much like how mathematics has BIDMAS which determines the order of evaluation of an expression Java and other program languages evaluate statements in a particulate way. This means within the Parentheses of a function you may include a statment instead of a variable or constant. This will be evaluated with the result (or return) been passed into the called function. This is why MvG says you can do lines.get(index - 1)

• Not all exceptions you should consider and plan around will the compiler inform you about. For example in your code an invalid input for line number or word number is entered you will get a Runtime Exception (array index out of bound)

• Naming of variables should be useful, you have index and index1. What’s the difference? I assume from reading your code one should be the user selected index of the line number and the second should be the index of the word on said line. May I suggest requestedLineIndex and requestedWordIndex.

On a final note this is not a usual StackOverflow question hence why your question has been ‘voted down’. If you are learning as part of a course is there a course forum or Virtual Learning Environment (VLE) you can post questions on? The support of your peers at the same level of learning tends to help with exploring the basics of a language.