Square Root

/* Without using sqrt() */
import java.io.*;
import java.util.Scanner;

class sqroot {

	/* Constructor of the class */
	sqroot(double no) {

		/* Relative error tolerance */
		double epsilon = 1e-15;

		/* Estimate of the square root of 'no' */
		double a = no;

		/* Repeatedly apply Newton update step until desired precision is achieved */
		while(Math.abs(a - no / a) > epsilon * a) {
			a = (no / a + a) / 2.0;
		}
		System.out.println("Square root of "+no+" = "+a);
	}
}
										
class squareroot {
	public static void main(String args[ ]) {
		Scanner input = new Scanner(System.in);
		System.out.println("Enter a number to calculate square root:");
		new sqroot(Double.parseDouble(input.nextLine()));
	}
}



/* Output */
Enter a number to calculate square root:
2

Square root of 2.0 = 1.414213562373095