How to compare input to txt file Strings stored in an array

Question

I have a txt file and I want to be able to compare input of a name to the names already on the file. I get a message "cannot find symbol" for the array that I have stored the txt file data in. I'm not sure if i am doing something wrong with storing the data in an array or what I need to do in order to get it be able to access the array from my for loop.

I get the error at the aryLines in for(String name : aryLines)

package binarysearch;

import java.io.*;
import java.util.Scanner;
/**
 *
 * @author Timothy
 */
public class BinarySearch 
{
    public static void main(String[] args) throws IOException
    {
        String file_name = "C:/Users/Timothy/Documents/test.txt";

        try
        {
            ReadFile file = new ReadFile(file_name);
            String[] aryLines = file.OpenFile();
            /*
            for(int index = 0; index < aryLines.length; index++)
            {
                System.out.println(aryLines[index]);
            }
            */
        }

        catch(IOException error)
        {
            System.out.println(error.getMessage());
        }


        String newName;

        Scanner in = new Scanner(System.in);
        System.out.println("Enter a name to compare to list: ");
        newName = in.nextLine();

        for(String name : aryLines)
        {
            if(name.equalsIgnoreCase(newName))
            {
                System.out.println("This name has already been added");
            }
            else
            {
                WriteFile data = new WriteFile(file_name, true);
                data.writeToFile("/n" + newName);
            }
        }

    }
}

WriteFile class

package binarysearch;

import java.io.*;
import java.util.Scanner;
/**
 *
 * @author Timothy
 */
public class WriteFile 
{
    private String path;
    private boolean append_to_file = false;

    public WriteFile(String file_path) 
    {
        path = file_path;
    }

    public WriteFile(String file_path, boolean append_value)
    {
        path = file_path;
        append_to_file = append_value;
    }

    public void writeToFile(String textLine) throws IOException
    {
        FileWriter write = new FileWriter(path, append_to_file);
        PrintWriter print_line = new PrintWriter(write);
        print_line.printf("%s" + "%n", textLine);
        print_line.close();
    }
}

ReadFile Class

package binarysearch;
import java.io.*;
/**
 *
 * @author Timothy
 */
public class ReadFile 
{
    private String path;

    public ReadFile(String file_path)
    {
        path = file_path;
    }

    public String[] OpenFile() throws IOException
    {
        FileReader read = new FileReader(path);
        BufferedReader textReader = new BufferedReader(read);
        int numberOfLines = readLines();
        String[] textData = new String[numberOfLines];

        for(int index = 0; index < numberOfLines; index++)
        {
            textData[index] = textReader.readLine();
        }

        textReader.close();
        return textData;
    }

    int readLines() throws IOException
    {
        FileReader file_to_read = new FileReader(path);
        BufferedReader buffer = new BufferedReader(file_to_read);

        String aLine;
        int numberOfLines = 0;

        while((aLine = buffer.readLine()) != null)
        {
            numberOfLines++;
        }

        buffer.close();
        return numberOfLines;
    }
}

Kunjan Thadani · Accepted Answer · 2014-11-03 07:23:45Z

There are a few problems in the class BinarySearch:

You are declaring String[] aryLines inside a try block. So its scope is restricted to the try block. Therefore, you are getting an error at aryLines in for(String name : aryLines), as it cannot find it declared because of the scope.
You need to give a break statement. Currently because of its absence, newName is written as many times as the if condition fails.
You need to write a new line character as '\n' and not as '/n'.

I have made the required changes in the class BinarySearch:

package binarysearch;

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

/**
 *
 * @author Timothy
 */
public class BinarySearch {

    private static boolean write=false;

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

        String file_name = "C:\\Users\\Timothy\\Documents\\test.txt";
        String[] aryLines = {};        
        try {
            ReadFile file = new ReadFile(file_name);
            aryLines = file.OpenFile();

        } catch (IOException error) {
            System.out.println(error.getMessage());
        }

        String newName;

        Scanner in = new Scanner(System.in);
        System.out.println("Enter a name to compare to list: ");
        newName = in.nextLine();

        for (String name : aryLines) {
            if (name.equalsIgnoreCase(newName)) {
                System.out.println("This name has already been added");
                write = false;
                break;
            } else {
                write = true;
            }
        }
        if (write == true) {
            WriteFile data = new WriteFile(file_name, true);
            data.writeToFile("\n" + newName);
            System.out.println("New name added successfully");
         }
    }
}

There can be any different logic for breaking the loop and writing the file. Currently a working solution is provided.

Ruchira Gayan Ranaweera · Accepted Answer · 2014-11-03 05:28:09Z

0

In here you need a break the loop if found. Else it will check other with other elements.

for(String name : aryLines){
   if(name.equalsIgnoreCase(newName)){
      System.out.println("This name has already been added");
      break; // word is found need to stop iteration further. 
    }else{
      WriteFile data = new WriteFile(file_name, true);
      data.writeToFile("/n" + newName);
    }
}

answered Nov 3, 2014 at 5:28

Ruchira Gayan Ranaweera

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