已知 sqrt (2)约等于 1.414，要求不用数学库，求 sqrt (2)精确到小数点后 10 位

yum install -y gcc
yum install -y gcc-c++
yum install -y cmake3

编辑~/.zshrc，增加一行，设置别名

alias cmake="cmake3"

#include <stdio.h>
#include <cmath>

int main() {
    double left = 1.41;
    double right = 1.42;

    double current = 0.0d;
    double result = 0.0d;

    int loop_count = 0;
    while (true) {
        ++loop_count;
        current = (left + right)/2;
        result = current * current;

        if (fabs(result - 2.0d) < 0.0000000000001d) {
            break;
        }

        if (result < 2.0d) {
            left = current;
        } else {
            right = current;
        }
    }

    printf("current:%lf, loop:%d, result:%lf", current, loop_count, result);
    return 1;
}

cmake_minimum_required (VERSION 2.8)
project (sqrttest)
add_executable(Demo sqrt.cpp)