Get Simplified Rational Number of two given Numbers using Java

The preceding Java code will give resultant rational number of two given numbers.

import java.io.*;
class rational
{
    public rational() {}
    public long gcd(long a, long b)
    {
        if (b == 0) return a;
        else return gcd(b, a % b);
    }
}
public class Rational
{
    public static void main(String args[]) throws IOException
    {
        rational r = new rational();
        long a, b, x, y;
        String str;
        DataInputStream in = new DataInputStream(System. in );
        System.out.print("Enter the 1st value: ");
        str = in .readLine();
        a = Integer.parseInt(str);
        System.out.print("Enter the 2nd value: ");
        str = in .readLine();
        b = Integer.parseInt(str);
        long l = r.gcd(a, b);
        System.out.println();
        System.out.println("The GCD of the given rational number is: " + l);
        x = a / l;
        y = b / l;
        System.out.println();
        System.out.println("The simplified rational number is: " + x + "/" + y);
    }
}

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