用C#写一个抽象类，有抽象属性，一个正方形类，一个正方体类，重写属性，输入一个边长值，求正方体的面积

Answer 1

//抽象类Shape
public abstract class Shape {
private double _areaValue;

public double AreaValue {
get { return _areaValue; }
set { _areaValue = value; }
}

public abstract double area(double length);
}

//正方形类 Square
public class Square : Shape {

public override double area(double length) {
AreaValue = length * length; //正方形面积=边长×边长
return AreaValue;
}
}

//正方体类 Cube
public class Cube : Shape {

public override double area(double length) {
AreaValue = length * length * 6; //正方体表面积=边长×边长×6
return AreaValue;
}
}

测试：
...
Square s = new Square();
Console.WriteLine("正方形面积: {0}", s.area(3.88));

Cube c = new Cube();
Console.WriteLine("正方体面积: {0}", c.area(3.88));
...