Question

创建Rectangle 的类用java

创建一个Rectangle类。该类拥有属性lenghth和width,每个属性的默认值为1；该类拥有的方法perimeiter和area，分别用于计算矩形的周长和面积；该类还有设置和读取属性length和width的方法，设置方法应能检查length和width的属性是否为小于20.0的浮点数。

Answer 1

class Rectangle {
double width=1;
double height=1;
public Rectangle(double width,double height)
{
this.width=width;
this.height=height;

}
public void setwidth(double w)
{width=w;
}
public void setheight(double h)
{height=h;
}

public double getwidth()
{return width;
}

public double getheight()
{return height;
}
public boolean f()
{if(width<20&&height<20) return true;
else return false;
}

public void area()
{

System.out.println("这个矩形的面积是："+width*height);
}
public void perimeter()
{

System.out.println("这个矩形的周长是："+2*(width+height));
}

}
public class RectangleDemo
{
public static void main(String[] args) {

Rectangle r1=new Rectangle(4,6);
Rectangle r2=new Rectangle(4,7);
r1.area();
r1.perimeter();
r2.area();
r2.perimeter();

}

}