pow binary, Java - rextester

pow binary

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//'main' method must be in a class 'Rextester'.
//Compiler version 1.8.0_111

import java.util.*;
import java.lang.*;

class Rextester
{  
    public static void main(String args[])
    {
        System.out.println("Hello, World!");
        
        System.out.println(power(2.0, 1000));
    }
    
    public static double power(double x, int y){
        double result = 1.0;
        long power = y;
        if (y < 0) {
            power = -power;
            x = 1.0 / x ;
        }
        int i = 0;
        while (power != 0) {
            System.out.println("================= iter " + ++i);
            System.out.println("power = " + power + " binary = " + Long.toBinaryString(power));
            System.out.println("in result = " + result);
            System.out.println("x = " + x);
            if ((power & 1) != 0) {
                result *= x;
            }
            x *= x ;
            power >>= 1 ;
            System.out.println("out result = " + result);
        }
        return result ;
    }
}

[ + ] Show input
Compilation time: 0.73 sec, absolute running time: 0.25 sec, cpu time: 0.26 sec, memory peak: 18 Mb, absolute service time: 0,99 sec

Hello, World! ================= iter 1 power = 1000 binary = 1111101000 in result = 1.0 x = 2.0 out result = 1.0 ================= iter 2 power = 500 binary = 111110100 in result = 1.0 x = 4.0 out result = 1.0 ================= iter 3 power = 250 binary = 11111010 in result = 1.0 x = 16.0 out result = 1.0 ================= iter 4 power = 125 binary = 1111101 in result = 1.0 x = 256.0 out result = 256.0 ================= iter 5 power = 62 binary = 111110 in result = 256.0 x = 65536.0 out result = 256.0 ================= iter 6 power = 31 binary = 11111 in result = 256.0 x = 4.294967296E9 out result = 1.099511627776E12 ================= iter 7 power = 15 binary = 1111 in result = 1.099511627776E12 x = 1.8446744073709552E19 out result = 2.028240960365167E31 ================= iter 8 power = 7 binary = 111 in result = 2.028240960365167E31 x = 3.4028236692093846E38 out result = 6.901746346790564E69 ================= iter 9 power = 3 binary = 11 in result = 6.901746346790564E69 x = 1.157920892373162E77 out result = 7.99167628880894E146 ================= iter 10 power = 1 binary = 1 in result = 7.99167628880894E146 x = 1.3407807929942597E154 out result = 1.0715086071862673E301 1.0715086071862673E301