在我的输出中只需要两个小数位

Question

如何获取小数点后仅两位数的双倍值。如果我的身高输入为72，体重为170，则收到的输出给出BMI=23.053626543209877。我不知道如何去掉.05后的尾随数字

import java.util.Scanner;

private static Scanner scanner;


public static void main(String[] args) {

    // Variables
    double height; 
    double weight; 
    double bmi; 

    Scanner keyboard = new Scanner(System.in);

    System.out.println("Please enter your height: ");
    height = keyboard.nextDouble();

    if(height<=0)
    {
        System.out.println("That's an invalid height.");
        return;
    }

    System.out.println("Please enter your weight: ");
    weight = keyboard.nextDouble();

    if(weight<=0)
    {
        System.out.println("That's an invalid weight.");
        return;
    }

    bmi =  calculateBMI(height, weight);


    System.out.println("BMI = " + bmi);

    System.out.println(bmiDescription(bmi));

    keyboard.close();
}


static double calculateBMI (double height, double weight) {
    return weight * 703 / (height * height);
}


static String bmiDescription (double bmi) {
    if (bmi < 18.5) {
        return "You are underweight.";
    } else {
        if (bmi > 25) {
            return "You are overweight.";
        } else {
            return "You are optimal.";
        }
    }
}

Answer 1

您可以将格式化的io与printf一起使用，例如

double bmi = 23.053626543209877;
System.out.printf("BMI = %.2f%n", bmi);

输出（我相信你想要的，甚至会执行四舍五入）

BMI = 23.05