Java 程序计算圆的直径、周长和面积

编写一个Java程序，通过示例找出圆的直径、周长和面积。此示例允许输入圆的半径，并使用数学公式计算直径、面积和周长。

• 圆的直径 = 2 * 半径
• 圆的面积 = π * 半径²
• 圆的周长 = 2 * π * 半径

package Area;

import java.util.Scanner;

public class DCAOfCricle1 {

	private static Scanner sc;

	public static void main(String[] args) {
		sc = new Scanner(System.in);	
		double radius, diameter, area, circumference;	

		System.out.print("Please Enter the Circle radius = ");
		radius = sc.nextDouble();	
	
		diameter = 2 * radius;
		area = Math.PI * radius * radius; 
		circumference = 2 * Math.PI * radius;

		System.out.println("\nArea of a Circle        = " + area);
		System.out.println("Diameter of a Circle      = " + diameter);
		System.out.println("Circumference of a Circle = " + circumference);
	}
}

这个程序声明了calcDiameter、calcArea和calCircumference函数，它们分别返回圆的直径、周长和面积。

package Area;

import java.util.Scanner;

public class DCAOfCricle2 {

	private static Scanner sc;

	public static void main(String[] args) {
		sc = new Scanner(System.in);
		
		double radius, diameter, area, circumference;
		
		System.out.print("Please Enter = ");
		radius = sc.nextDouble();
		
		diameter = calcDiameter(radius);
		area = calcArea(radius); 
		circumference = calCircumference(radius);

		System.out.println("\nArea of a Circle        = " + area);
		System.out.println("Diameter of a Circle      = " + diameter);
		System.out.println("Circumference of a Circle = " + circumference);
	}
	
	public static double calcDiameter(double radius) {
		return 2 * radius;
	}
	public static double calcArea(double radius) {
		return Math.PI * radius * radius;
	}
	public static double calCircumference(double radius) {
		return 2 * Math.PI * radius;
	}
}

Please Enter = 12

Area of a Circle        = 452.3893421169302
Diameter of a Circle      = 24.0
Circumference of a Circle = 75.39822368615503