【优化版】取近似浮点数 四舍五入

import LogUtil.logUtil;

import java.util.Scanner;





public class Test711 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        //扫描输入一个数
        String sub = scanner.nextLine();
        //先判断是否包含 小数点
        if (sub.contains(".")) {
            //获取第一次出现的小数点的位置
            int indexOf = sub.indexOf(".");
            //获取小数点后一位的数
            String substring = sub.substring(indexOf);
            String newSub = "0" + substring;
            double vSub = Double.parseDouble(newSub);
            //r如果这个值 小于0.5 那就舍弃
            if (vSub < 0.5) {
                //向下取值
                double vOld = Double.parseDouble(sub) - vSub;
                String sVOld = String.valueOf(vOld);
                //取小数点之前的数
                String substring1 = sVOld.substring(0, indexOf);
                System.out.println(substring1);
            } else {
                //反之向上取值 0.6 -> 1
                double newV = Double.parseDouble(sub) - vSub + 1;
                String sNewV = String.valueOf(newV);
                //截取小数点之前的数 向上取值之后 截取
                String substring1 = sNewV.substring(0, indexOf);
                System.out.println(substring1);
            }
        } else {
            logUtil.error("这不是小数，你输入的啥玩意");
        }
    }
}

import java.util.Scanner;

public class Test714 {
    //q取近似值 四舍五入
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextDouble()) {
            double result = scanner.nextDouble();
            //max 类的方法
            long round = Math.round(result);
            System.out.println(round);
        }
    }
}