正方形继承矩形的代码问题

[Greg_han]

继承的用法有些困惑，请大家看看这段代码：正方形的面积输出有问题
class Program
{
static void Main(string[] args)
{
circular c = new circular(5);
Console.WriteLine(c.CalculateArea());

rectangle r = new rectangle(3,6);
Console.WriteLine(r.CalculateArea());

square s = new square(8);
Console.WriteLine(s.CalculateArea()); //应该输出64，怎么输出了0？
Console.Read();
}


public abstract class Graph
{
public abstract double CalculateArea();
}


public class circular : Graph
{
private double radius; //半径

public circular()
{
radius = 0;
}

public circular(double _radius)
{
radius = _radius;
}

public void SetRadius(double _radius)
{
radius = _radius;
}

public double GetRadius()
{
return radius;
}

public override double CalculateArea() //子类使用父类的方法
{
return GetRadius() * 3.1415;
}
}


public class rectangle : Graph
{
double length;
private double width;

public rectangle()
{
length = 0;
width = 0;
}

public rectangle(double _length, double _width)
{
length = _length;
width = _width;
}

public double GetLength()
{
return length;
}

public double GetWideh()
{
return width;
}

public void SetLength(double _length)
{
length = _length;
}

public void SetWidth(double _width)
{
width = _width;
}

public override double CalculateArea() //子类使用父类的方法
{
return length * width;
}
}

public class square : rectangle
{

public square()
{
base.SetLength(0);
base.SetWidth(0);
}

public square(double side_length)
{
base.SetLength(side_length);
base.SetLength(side_length);
base.GetLength();
base.GetWideh();
}

new public double CalculateArea() //子类使用父类的方法
{
return base.CalculateArea();
}
}
}

[michaelnami]

new public double CalculateArea() //子类使用父类的方法
{
return base.CalculateArea();
}
是不是和这个NEW有关

[兔子-顾问]

base.SetLength(side_length);
base.SetLength(side_length);

写错了嘛，有一个是base.SetWidth(side_length);
对吧

[兔子-顾问]

学会debug，这些就不成问题了。

[hustcyb]

这个问题还不好解决
先给为正方形和矩形抽象出一个虚拟的基类RectangleBase:

    public abstract class RectangleBase : Graph
    {
        #region Properties

        public abstract double Length
        {
            get;
            set;
        }

        public abstract double Width
        {
            get;
            set;
        }

        #endregion

        #region Graph Members

        public override double CalculateArea()
        {
            return Length * Width;
        }

        #endregion
    }

然后让矩形和长方形分别继承自此虚拟基类

    public class Rectangle : RectangleBase
    {
        #region Fields

        private double length;

        private double width;

        #endregion

        #region Constructors

        public Rectangle()
            : this(0, 0)
        {
        }

        public Rectangle(double _length, double _width)
        {
            length = _length;
            width = _width;
        }

        #endregion

        #region RectangleBase Members

        public override double Length
        {
            get
            {
                return this.length;
            }
            set
            {
                this.length = value;
            }
        }

        public override double Width
        {
            get
            {
                return this.length;
            }
            set
            {
                this.length = value;
            }
        }

        #endregion
    }

    public class Square : RectangleBase
    {
        #region Fields

        private double side;

        #endregion

        #region Constructors

        public Square()
            : this(0)
        {
        }

        public Square(double side)
        {
            this.side = side;
        }

        #endregion

        #region RectangleBase Members

        public override double Length
        {
            get
            {
                return this.side;
            }
            set
            {
                this.side = value;
            }
        }

        public override double Width
        {
            get
            {
                return this.side;
            }
            set
            {
                this.side = value;
            }
        }

        #endregion
    }

[criedshy]

public square(double side_length) 
                { 
                    base.SetLength(side_length); 
                    base.SetLength(side_length); 
                    base.GetLength(); 
                    base.GetWideh(); 
                } 

你有两个base.SetLength(side_length); 你的width还是0，所以得出值还是0

[zzx509]

正方形的带参构造错了，宽度没有设置。
base.SetLength(side_length);
base.SetLength(side_length);

这个new public double CalculateArea()方法是多余的，要不要没有关系。