我无法让我的程序输出在 Java 中正确对齐

Question

这些是说明... 编写一个类来计算行星的测量值。

1. 用这些方法编写一个类。

   • 以英里为单位初始化行星圆周的构造函数或 公里
   • 计算行星测量值的方法 - 圆、面积、直径、半径、曲面、面积、体积

2. 使用你的类编写一个程序 - 询问用户行星的周长 - 创建一个行星对象 - 用逗号和小数打印行星的测量值 - 确保小数对齐。

package com.company;
import java.util.Scanner;
import java.lang.reflect.Field;

public class Main {

    public static void main(String[] args) {
        Main planet = new Main();
        Scanner in = new Scanner(System.in);
        classP cP = new classP();


        //cP.getRadius();
        //cP.getCirleArea();
        //cP.getcirc();

    }
}

package com.company;
import java.util.Scanner;
import java.lang.Math;
import java.text.DecimalFormat;

public class classP {
    private double circ, radius, circleArea, surfArea, volume;
    //public classP radius;
    //public double circ;
    //public double circleArea;

    public Main planet = new Main();

    public classP() {
        this.circ = circ;
        this.radius = radius;
        this.circleArea = circleArea;
        this.surfArea = surfArea;
        this.volume = volume;

        Main mainClass = new Main();
        Scanner in = new Scanner(System.in);
        DecimalFormat df = new DecimalFormat("###,###,###.##");

        System.out.print("What is the planet's circumference in miles?  ");
        double circ = in.nextDouble();
        double radius = circ / (Math.PI * 2);
        double circleArea = Math.PI * Math.pow(radius, 2);
        System.out.printf("%nThe radius of the planet is: " + "%,12.1f\n" , radius);
        System.out.printf("%nThe area of the planet is: " + "%,12.1f\n", circleArea);
        double diameter = circ / Math.PI;
        System.out.printf("%nThe diameter of the planet is: " + "%,12.1f\n", diameter);
        double surfArea = 4 * Math.PI * Math.pow(radius, 2);
        System.out.printf("%nThe surface area of the planet is: " + "%,12.1f\n", surfArea);
        double volume = (4.0 / 3) * Math.PI * Math.pow(radius, 3);
        System.out.printf("%nThe volume of the planet is: " + "%,12.1f\n", volume);
    }


    //public final double getcirc(){
    //    return this.circ;
    //}
    //public final classP getRadius(){
    //    return this.radius;
    //}
    //public final double getCirleArea() {
    //    return this.circleArea;
    //}
}

这是我的输出，示例用户输入为：100

What is the planet's circumference in miles?  100

The radius of the planet is:         15.9

The radius of the planet is: 15.9        

The area of the planet is:        795.8

The area of the planet is: 795.8       

The diameter of the planet is: 31.8                          

The surface area of the planet is: 3,183.1                       

The volume of the planet is: 16,886.9 

Answer 1

需要对您的代码进行一些基本的改进。代码块中存在许多不必要的代码。我试图组织它们。它可以指导你。

对于类似的打印，使用String.format 创建具有打印机功能的自定义模板。实际上很容易维护。

代码：

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Main planet = new Main();
        Scanner in = new Scanner(System.in);
        
        System.out.print("What is the planet's circumference in miles?  ");
        double circ = in.nextDouble();
        
        ClassP cP = new ClassP(circ);
        cP.calculateData();
        cP.print();

    }

}

class ClassP{
    
    private double circ, radius, circleArea, diameter, surfArea, volume;

    public ClassP(double circ) {
        this.circ = circ;  
    }
    
    public void calculateData() {
        radius = circ / (Math.PI * 2);
        circleArea = Math.PI * Math.pow(radius, 2);
        diameter = circ / Math.PI;
        surfArea = 4 * Math.PI * Math.pow(radius, 2);
        volume = (4.0 / 3) * Math.PI * Math.pow(radius, 3);
        
    }
    
    public void print() {
        customAlignPrinter("The radius of the planet is:", radius);
        customAlignPrinter("The area of the planet is:", circleArea);
        customAlignPrinter("The diameter of the planet is:",diameter);
        customAlignPrinter("The surface area of the planet is:", surfArea);
        customAlignPrinter("The volume of the planet is:", volume);
    }
    
    public void customAlignPrinter(String msg,double val) {
        System.out.println(String.format("%40s %,20f", msg, val));
    }
    
}

输出控制台：

What is the planet's circumference in miles?  100
            The radius of the planet is:            15.915494
              The area of the planet is:           795.774715
          The diameter of the planet is:            31.830989
      The surface area of the planet is:         3,183.098862
            The volume of the planet is:        16,886.863940

Answer 2

您需要创建一个格式字符串，您可以将标签传递给该格式字符串，以指定一个足够大的填充空间以容纳最长的空间。

package com.company;
import java.util.Scanner;
import java.lang.Math;
import java.text.DecimalFormat;

class classP {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("What is the planet's circumference in miles?  ");

        double circ = in.nextDouble();
        double radius = circ / (Math.PI * 2);
        double circleArea = Math.PI * Math.pow(radius, 2);

        System.out.println();

        String format = "%35s %,12.1f\n";

        System.out.printf(format, "The radius of the planet is" , radius);
        System.out.printf(format, "The area of the planet is", circleArea);
        double diameter = circ / Math.PI;
        System.out.printf(format, "The diameter of the planet is", diameter);
        double surfArea = 4 * Math.PI * Math.pow(radius, 2);
        System.out.printf(format, "The surface area of the planet is", surfArea);
        double volume = (4.0 / 3) * Math.PI * Math.pow(radius, 3);
        System.out.printf(format, "The volume of the planet is", volume);
    }
}

结果：

What is the planet's circumference in miles?  100

        The radius of the planet is         15.9
          The area of the planet is        795.8
      The diameter of the planet is         31.8
  The surface area of the planet is      3,183.1
        The volume of the planet is     16,886.9