reatest Common Divisor GCD Using Recursion Write one program

reatest Common Divisor (GCD) Using Recursion:

Write one program to satisfy the following:

1. Write a program that will read each line from A1.txt.
2. Show the GCD of the numbers in each line of the input file (using recursion) in a output file B1.txt.
3. Each line in A1.txt will correspond to each line of B1.txt.
*****Note: A single line of A1.txt may contain two/three integer numbers. First three lines are given as sample.

A1.txt :

Sample input

5 7

12 15

80 40 100

Sample Output Format:

1

3

20

Solution

import java.io.BufferedWriter;

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

public class GCDRecursion {
   /**
   * method to find gcd of m and n
   *
   * @param m
   * @param n
   * @return
   */
   static int gcd(int m, int n) {
       if (n == 0)
           return m;
       else if (n > m)
           return gcd(n, m);
       else
           return gcd(n, m % n);
   }

   /**
   * @param args
   */
   public static void main(String[] args) {
       Scanner scanner = null;

       try {
           File file = new File(\"B1.txt\");

           // if file doesnt exists, then create it
           if (!file.exists()) {
               file.createNewFile();
           }
           scanner = new Scanner(new File(\"A1.txt\"));

           FileWriter fw = new FileWriter(file.getAbsoluteFile());
           BufferedWriter bw = new BufferedWriter(fw);

           while (scanner.hasNext()) {
               String line = scanner.nextLine();
               String[] lineArr = line.split(\" \");
               int gcdValue;
               if (lineArr.length == 2) {
                   gcdValue = gcd(Integer.parseInt(lineArr[0]),
                           Integer.parseInt(lineArr[1]));

               } else {
                   gcdValue = gcd(
                           Integer.parseInt(lineArr[2]),
                           gcd(Integer.parseInt(lineArr[0]),
                                   Integer.parseInt(lineArr[1])));
               }
               bw.write(gcdValue + \"\ \");

           }
           bw.close();
       } catch (Exception e) {
           // TODO: handle exception
       } finally {

           scanner.close();
       }
   }
}

A1.txt

5 7
12 15
80 40 100
6 18
70 100 25
30 9
72 48 16
10 15
16 20
128 48 24

B1.txt

1
3
20
6
5
3
8
5
4
8