總體框架

public   class Rectangle()

{

1\private double width;

2\private double length;

3\public Rectangle(double width,double length)

4\public Rectangle(){}//不帶引數的構造方法

5\public void output(){輸出}

6\public double perimeter(){}

7\public double area(){}

8\public void staic void main(){函式的呼叫}

}

package ch01;
//JAVA程式設計
import java.util.Scanner;//Scanner大寫
public class Rectangle {
//屬性成員
	private double width;
	private double length;
	//利用width和length建立構造方法
	public Rectangle(double width,double length)
	{
		this.length=length;
		this.width=width;
		
	}
	//不帶引數的構造方法
	public Rectangle() {
	//省略get和set方法	
}
	//輸出長方形的長寬資訊
	public void output()
	{
		System.out.println("長方形的長為:"+length);
		System.out.println("長方形的寬為"+width);
        System.out.println("長方形的面積為"+area());
        System.out.println("長方形的周長為"+perimeter());
	}
	//計算長方形的周長
	public double perimeter()
	{
		return 2*width*length;
	}
	public double area()
	{
		return 2*(length+width);
	}
	public static void main(String[] args)
	{
		Scanner scanner=new Scanner(System.in);
		System.out.println("please input Rectangle's length:");
		double length=scanner.nextDouble();
		System.out.println("please input Rectangle's width:");
		double width=scanner.nextDouble();
		//利用構造方法建立一個Rectangle型別的物件
		Rectangle rectangle=new Rectangle(width,length);
		rectangle.output();//方法的呼叫形式為物件.方法名;如果該方法是有static關鍵字修飾,則呼叫方法為
		//類名.方法名
	}
}