Question

要求定义一个描述形状的抽象类shape，类内包括求面积的area和求各图形总面积的total函数。

1.从shape派生出三角形，圆形，正方形类，要求类中有构造函数，修改显示成元值的函数，求面积的函数。
2.写main（）函数，计算三边为7,8,9的三角形，边长为9.9的正方形和半径为4的圆形（必须调用total函数计算） 诸位大侠帮忙忙吧。。。考试要用。。。谢谢啦
程序问题不大，关键是total函数，怎么在shape类中声明定义，以及是在main函数中，怎样调用。。。谢谢大家，希望可以针对问题。。。

Answer 1

class Trapezoid : public Shape
{
private:
double top;
double bottom;
double height;
public:
Trapezoid(double t, double b, double h)
{
top = t;
bottom = b;
height = h;
}

double Area()
{
return (top + bottom) * height / 2;
}
};

#define PI 3.1415926
class Circle : public Shape
{
private:
double r;
public:
Circle(double r)
{
this->r = r;
}

double Area()
{
return PI * r * r;
}
};

class Triangle : public Shape
{
private:
double bottom;
double height;
public:
Triangle(double b, double h)
{
bottom = b;
height = h;
}

double Area()
{
return bottom * height / 2;
}
};

Answer 2

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
public abstract class Shapes
{
protected int _xval;
protected int _yval;
protected int _width;
protected int _height;
public abstract void draw();

}
public class Circle:Shapes
{
public Circle(int xvalue, int yvalue, int widthvalue, int heightvalue)
{
this._xval = xvalue;
this._yval = yvalue;
this._width = widthvalue;
this._height = heightvalue;
}
public override void draw()
{
Console.WriteLine("用于绘制圆的值为：");
Console.WriteLine("x坐标={0}",this._xval);
Console.WriteLine("y坐标={0}",this._yval);
Console.WriteLine("宽={0}", this._width);
Console.WriteLine("高={0}", this._height);
}
}
class Program
{
static void Main(string[] args)
{
Circle c = new Circle(2,2,5,5);
c.draw();
Console.Read();
}
}
}