Question

Please make a method in Java that will allow me to find a String in a file using recursion. The details are the following:

Search the input file line by line for a given string. The output must contain the line number, followed by the contents of the line that contains the search argument. For instance given the following the search string: Java, the program would search the file line by line generating a result such as the following:

50: on the island of Java

95: The people of JAVA loves jaVa.

Use recursion to search the file.

Answer 1

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

public class SearchFileRecursive {

    public static void search(Scanner fin, String word, int lineNumber) {
        if (fin.hasNextLine()) {
            String line = fin.nextLine();
            if (line.toLowerCase().contains(word.toLowerCase())) {
                System.out.println(lineNumber + ": " + line);
            }
            search(fin, word, lineNumber+1);
        }
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter file name: ");
        File file = new File(in.nextLine());
        try {
            Scanner fin = new Scanner(file);
            System.out.print("Enter a word to search for: ");
            String word = in.nextLine();
            search(fin, word, 1);
            fin.close();
        } catch (FileNotFoundException e) {
            System.out.println(file.getAbsolutePath() + " does not exists!");
        }
        in.close();
    }
}