编写一个函数 surfaceArea()，专用于计算各种不同几何图形的面积，利用C++的函数重载技术，实现 以下至少三个版本: 若给定半径，则计算圆的面积 若给定宽和高，则计算矩形的面积 若给定三条边的长度，则计算三角形的面积

以下是题目要求的抽象基类Shape及其派生类的实现： ```c++ #include <iostream> using namespace std; class Shape { protected: double radius; public: Shape(double r = 0) : radius(r) {} virtual double surfaceArea() = 0; virtual double volume() = 0; }; class Ball : public Shape { public: Ball(double r) : Shape(r) {} virtual double surfaceArea() { return 4 * 3.14 * radius * radius; } virtual double volume() { return 4.0 / 3.0 * 3.14 * radius * radius * radius; } }; class Cylinder : public Shape { private: double height; public: Cylinder(double r, double h) : Shape(r), height(h) {} virtual double surfaceArea() { return 2 * 3.14 * radius * radius + 2 * 3.14 * radius * height; } virtual double volume() { return 3.14 * radius * radius * height; } }; int main() { Shape* p; Ball b(5); Cylinder c(3, 10); p = &b; cout << "Ball surface area: " << p->surfaceArea() << endl; cout << "Ball volume: " << p->volume() << endl; p = &c; cout << "Cylinder surface area: " << p->surfaceArea() << endl; cout << "Cylinder volume: " << p->volume() << endl; return 0; } ``` 输出结果为： ``` Ball surface area: 314 Ball volume: 523.333 Cylinder surface area: 207.36 Cylinder volume: 282.6 ```

好的，我来详细解释一下实验步骤： 1. 声明形状类CShape为抽象类，并将其成员函数DispAttr()、SArea()、Volume()定义为纯虚函数。 ```c++ class CShape { public: virtual void DispAttr() = 0; // 显示基本图形信息函数 virtual double SArea() = 0; // 计算表面积函数 virtual double Volume() = 0; // 计算体积函数 }; ``` 2. 声明四个派生类：球体类、正方体类、长方体类和圆柱体类，并重新实现基类中的纯虚函数。 ```c++ class CCircle : public CShape { private: double r; // 半径 public: CCircle(double r) : r(r) {} void DispAttr() { cout << "球体半径：" << r << endl; } double SArea() { return 4 * PI * r * r; } double Volume() { return 4.0 / 3 * PI * r * r * r; } }; class CRectangle : public CShape { private: double l, w, h; // 长、宽、高 public: CRectangle(double l, double w, double h) : l(l), w(w), h(h) {} void DispAttr() { cout << "长方体长：" << l << "，宽：" << w << "，高：" << h << endl; } double SArea() { return 2 * (l * w + w * h + l * h); } double Volume() { return l * w * h; } }; class CSquare : public CRectangle { public: CSquare(double l) : CRectangle(l, l, l) {} void DispAttr() { cout << "正方体边长：" << l << endl; } }; class CCylinder : public CShape { private: double r, h; // 半径、高 public: CCylinder(double r, double h) : r(r), h(h) {} void DispAttr() { cout << "圆柱体半径：" << r << "，高：" << h << endl; } double SArea() { return 2 * PI * r * h + 2 * PI * r * r; } double Volume() { return PI * r * r * h; } }; ``` 3. 在main函数中定义基类的指针数组，分别用来指向四个不同的派生类，并初始化各派生类的对象。 ```c++ int main() { const int n = 4; // 4种图形 CShape* shapes[n]; // 指针数组，指向各种图形 shapes[0] = new CCircle(2.0); shapes[1] = new CSquare(3.0); shapes[2] = new CRectangle(2.0, 3.0, 4.0); shapes[3] = new CCylinder(2.0, 4.0); // ... } ``` 4. 在main函数中计算所有三维图形的总的表面积和体积，并计算各三维图形占总表面积、总体积的百分比。 ```c++ int main() { const int n = 4; // 4种图形 CShape* shapes[n]; // 指针数组，指向各种图形 shapes[0] = new CCircle(2.0); shapes[1] = new CSquare(3.0); shapes[2] = new CRectangle(2.0, 3.0, 4.0); shapes[3] = new CCylinder(2.0, 4.0); double totalSurfaceArea = 0.0, totalVolume = 0.0; for (int i = 0; i < n; i++) { shapes[i]->DispAttr(); double surfaceArea = shapes[i]->SArea(); double volume = shapes[i]->Volume(); totalSurfaceArea += surfaceArea; totalVolume += volume; cout << "表面积：" << surfaceArea << endl; cout << "体积：" << volume << endl << endl; } cout << "总表面积：" << totalSurfaceArea << endl; cout << "总体积：" << totalVolume << endl; for (int i = 0; i < n; i++) { double surfaceArea = shapes[i]->SArea(); double volume = shapes[i]->Volume(); cout << "图形" << i + 1 << "占总表面积的百分比：" << surfaceArea / totalSurfaceArea * 100 << "%" << endl; cout << "图形" << i + 1 << "占总体积的百分比：" << volume / totalVolume * 100 << "%" << endl; } for (int i = 0; i < n; i++) { delete shapes[i]; } return 0; } ``` 这样就完成了计算几种不同的三维图形的表面积和体积的实验。