計算各種圖形的周長（接口與多態）

import java.util.Scanner;

class Rect {
	private double length;
	private double width;
	private double high;

	public Rect(double length) {
		this(length, length);
	}

	public Rect(double length, double width) {
		if (length < 0 || width < 0) {
			length = 0;
			width = 0;
		}

		this.length = length;
		this.width = width;
	}

	public Rect(double length, double width, double high) {
		if (length < 0 || width < 0 || high < 0) {
			length = 0;
			width = 0;
			high = 0;
		}

		this.length = length;
		this.width = width;
		this.high = high;
	}

	/*
	 * public int getlength() { return length; }
	 * 
	 * public void setlength(int length) { if (length < 0) { length = 0; }
	 * this.length = length; }
	 * 
	 * public int getwidth() { return width; }
	 * 
	 * public void setwidth(int width) { if (width < 0) { width = 0; }
	 * this.width = width; }
	 */

	public double rectanglelength(Rect rect) {
		return 2 * (rect.length + rect.width);
	}

	public double roundglelength(Rect rect) {
		return 3.14 * 2 * rect.length;
	}

	public double trianglelelength(Rect rect) {
		double tem = 0;
		if ((rect.length + rect.width > rect.high)
				&& (rect.width + rect.high > rect.length)
				&& (rect.length + rect.high > rect.width)) {
			tem = rect.length + rect.width + rect.high;
		}
		return tem;
	}

}

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner cin = new Scanner(System.in);
		while (cin.hasNext()) {
			Rect rect;
			String str = cin.nextLine();
			String[] arr = str.split(" ");
			double count = arr.length;
			if (count == 1) {
				double length = Integer.parseInt(arr[0]);
				rect = new Rect(length);
				System.out.printf("%.2f\n", rect.roundglelength(rect));

			} else if (count == 2) {
				double length = Integer.parseInt(arr[0]);
				double width = Integer.parseInt(arr[1]);
				rect = new Rect(length, width);
				System.out.printf("%.2f\n", rect.rectanglelength(rect));

			} else if (count == 3) {
				double length = Integer.parseInt(arr[0]);
				double width = Integer.parseInt(arr[1]);
				double high = Integer.parseInt(arr[2]);
				rect = new Rect(length, width, high);
				System.out.printf("%.2f\n", rect.trianglelelength(rect));

			}

		}
		cin.close();
	}

}