Calculating nth root in Java using power method

Question

I was trying to get a cubic root in java using Math.pow(n, 1.0/3) but because it divides doubles, it doesn\'t return the exact answer. For example, with 125, this g

Answer 1

Find nth root Using binary search method. Here is the way to find nth root with any precision according to your requirements.

import java.util.Scanner;

public class FindRoot {

    public static void main(String[] args) {
        try (Scanner scanner = new Scanner(System.in)) {
            int testCase = scanner.nextInt();
            while (testCase-- > 0) {
                double number = scanner.nextDouble();
                int root = scanner.nextInt();
                double precision = scanner.nextDouble();
                double result = findRoot(number, root, precision);
                System.out.println(result);
            }
        }
    }

    private static double findRoot(double number, int root, double precision) {
        double start = 0;
        double end = number / 2;
        double mid = end;
        while (true) {
            if (precision >= diff(number, mid, root)) {
                return mid;
            }
            if (pow(mid, root) > number) {
                end = mid;
            } else {
                start = mid;
            }
            mid = (start + end) / 2;
        }
    }

    private static double diff(double number, double mid, int n) {
        double power = pow(mid, n);
        return number > power ? number - power : power - number;
    }

    private static double pow(double number, int pow) {
        double result = number;
        while (pow-- > 1) {
            result *= number;
        }
        return result;
    }
}