实现sqrt算法

package com.company;


import org.junit.Test;

public class Lesson3_2 {

    /**
     * @Description: 计算大于1的正整数之平方根
     * @param n-待求的数, deltaThreshold-误差的阈值, maxTry-二分查找的最大次数
     * @return double-平方根的解
     */
    public static double getSqureRoot(int n, double deltaThreshold, int maxTry) {

        if (n <= 1) {
            return -1.0;
        }

        double min = 1.0, max = (double)n;
        for (int i = 0; i < maxTry; i++) {
            double middle = (min + max) / 2;
            double square = middle * middle;
            double delta = Math.abs((square / n) - 1);
            if (delta <= deltaThreshold) {
                return middle;
            } else {
                if (square > n) {
                    max = middle;
                } else {
                    min = middle;
                }
            }
        }

        return -2.0;

    }

    @Test
    public  void Test1()
    {
        int number = 10;
        double squareRoot = Lesson3_2.getSqureRoot(number, 0.000001, 10000);
        if (squareRoot == -1.0) {
            System.out.println("请输入大于1的整数");
        } else if (squareRoot == -2.0) {
            System.out.println("未能找到解");
        } else {
            System.out.println(String.format("%d的平方根是%f", number, squareRoot));
        }
    }
}