小编Che*_*vyb的帖子

这是我尝试创建的类:

package rectangle;

public class Rectangle
{
    private double length,width;

    public void setLength(double length)
    {
        length=this.length;
    }
    public void setWidth(double width)
    {
        width=this.width;
    } 
    public double getLength()
    {
        return length;
    }
    public double getWidth()
    {
        return width;
    }
    public double area()
    {
        return length*width;
    }
}

我相信我已经正确地上课了.我只是想创建并使用一个可以计算矩形区域的类.
然后我尝试实际创建实例对象:

/*Testing out the rectangle class*/
package rectangleclasstest;

import java.util.Scanner;

public class RectangleClassTest 
{

    static void main(String[] args) 
    {
        Scanner keyboard= new Scanner(System.in);
        Rectangle rec=new Rectangle();

        //get length
        System.out.println("Please enter the length");
        rec.setLength()=keyboard.nextInt(); …