Question

*JAVA

Prompt the user for a movie name. Output the three movies that come alphabetically before the one entered.

I need help correcting my code. I'm unsure why I am getting a name, year, and genre in my output.

Input: Jericho

Output:

Similar title finder. Enter a movie name.\n

Here are the 3 movies that are listed before the one you entered\n

Jeremy Paxman Interviews...\n

Jeremy Taylor\n

Jeremy Vine Meets...\n

Current output:

Similar title finder. Enter a movie name.\n

Here are the 3 movies that are listed before the one you entered\n

Jeremy Vine Meets...\n

2004\n

Documentary\n

(Your output is too short.)

Current code:

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

public class Movies {

    static ArrayList<String> moviesList;

    public static void main(String[] args) throws FileNotFoundException {
//providing file name
        File file = new File("db.txt");

        readNames(file);

        System.out.println("Similar title finder. Enter a movie name.");

        Scanner scanner = new Scanner(System.in);

        String movieName = scanner.nextLine();

        searchMovie(movieName);
    }

    public static void readNames(File file) throws FileNotFoundException {

        moviesList = new ArrayList<String>();

        Scanner scanner = new Scanner(new FileReader(file));

        while (scanner.hasNextLine()) {

            String name = scanner.nextLine();

            moviesList.add(name);

        }
    }

    public static void selectionSort(ArrayList<String> haystack) {
        //visit all elements but the last
        for (int startScan = 0; startScan < haystack.size() - 1; startScan++) {
            //assume first element is smallest
            int minIndex = startScan;
            String minValue = haystack.get(minIndex);

            //visit all remaining elements
            //if current element is smaller than what we know so far
            for (int index = startScan + 1; index < haystack.size(); index++) {

                if (haystack.get(index).compareTo(minValue) < 0) {
                    //keep track of smaller element
                    minValue = haystack.get(index);
                    minIndex = index;
                }
                //swap smaller element into place
                haystack.set(minIndex, haystack.get(startScan));
                haystack.set(startScan, minValue);
            }
        }
    }


    public static void searchMovie(String name) {

        if (!moviesList.contains(name)) {

            moviesList.add(name);

            Movies.selectionSort(moviesList);


            searchMovie(name);


            int index = moviesList.indexOf(name);

            moviesList.remove(index);
        }


        if (moviesList.contains(name)) {

            String data = "";

            int index = moviesList.indexOf(name);

            for (int i = 3; i >= 1; i--) {

                if (index - i >= 0) {

                    data += moviesList.get(index - i) + "\n";

                }

            }

            System.out.println("Here are the 3 movies that are listed before the one you entered");

            System.out.println(data);

        }

    }

}

please include explanations and avoid try/catch or collections. Thank you

Answer 1

SOLUTION: WHY THE OUTPUT CONTAINS EXTRA DATA? Your code has no error, the INOUT FILE you are using is containing extraneous data and this is why you are getting them in your output. Let's understand the following code first. 19- 20 public static void readNames (File file) throws FileNotFoundException { moviesList = new ArrayList<String> (); Scanner scanner = new Scanner(new FileReader(file)); while (scanner.hasNextLine()) { String name = scanner.nextLine(); moviesList.add(name); } 26 Here at line number 23, you are extracting the whole line (from the input file) and adding the same into the moviesList. As your input file holds extraneous data (such as year, and genre) this is also getting copied and being displayed in our uttput. HOW TO GET THE DESIRED OUTPUT? Option 1: Remove the extraneous data from the database file. Keep the required ones only. I.e. Movie name and remove year and genre. Option 2: (If you don't wish to delete the extraneous data) Add a character marker the end of the movie name. Use symbols like * or #etc. which can't certainly be a part of the movie name. ✓ And then split the Extracted line on the basis of this marker character. ✓ By doing this in the first portion you get the movie name and in the second portion you get all other details. ✓ Ignore the second part and add the first portion i.e. the movie name into the movieList and you are done.

CODE FOR SPLITTING: After the line number 23, add the following code. public static void readNames (File file) throws FileNotFoundException moviesList = new ArrayList<String> (); Scanner scanner = new Scanner(new FileReader(file)); while (scanner.hasNextLine()) { //Scan the whole line String name = scanner.nextLine(); //split the line into two parts assuming # as the marker String[] words = name.split("#"); //The first part i.e. the Movie name is to be added to the moviesList. moviesList.add (words[0]);

Can't provide a screenshot as you have not attached the database file.