声明抽象基类Shape，由它派生出5个派生类；Circle(圆形)、Square（正方形）、Rectangle（矩形）、Trapezoid（梯形）、Triangle（三角形），分别计算几种图形的面积，并求它们的和并显示出来。请按照要求选择如下一种方式编程实现。 注意圆周率取3.14. 实现方式： 1.使用继承和派生完成上述功能。 2.使用动态多态完成上述功能，提示：基类指针+派生类对象。 3. 使用派生类构造函数知识完成上述功能。

好的，我明白你的问题了。我将会给出三种不同的实现方式，你可以选择其中一种进行编程实现。

1. 使用继承和派生完成上述功能：

#include <iostream>
using namespace std;

class Shape {
public:
    virtual float area() = 0;  // 抽象基类，计算面积
};

class Circle : public Shape {
private:
    float radius;
public:
    Circle(float r) { radius = r; }
    float area() { return 3.14 * radius * radius; }
};

class Square : public Shape {
private:
    float side;
public:
    Square(float s) { side = s; }
    float area() { return side * side; }
};

class Rectangle : public Shape {
private:
    float length, width;
public:
    Rectangle(float l, float w) { length = l; width = w; }
    float area() { return length * width; }
};

class Trapezoid : public Shape {
private:
    float top, bottom, height;
public:
    Trapezoid(float t, float b, float h) { top = t; bottom = b; height = h; }
    float area() { return (top + bottom) * height / 2; }
};

class Triangle : public Shape {
private:
    float base, height;
public:
    Triangle(float b, float h) { base = b; height = h; }
    float area() { return base * height / 2; }
};

int main() {
    Shape *shapes[5];
    shapes[0] = new Circle(5);
    shapes[1] = new Square(4);
    shapes[2] = new Rectangle(3, 5);
    shapes[3] = new Trapezoid(2, 4, 3);
    shapes[4] = new Triangle(3, 4);

    float total_area = 0;
    for (int i = 0; i < 5; i++) {
        total_area += shapes[i]->area();
    }
    cout << "Total area: " << total_area << endl;

    for (int i = 0; i < 5; i++) {
        delete shapes[i];
    }
    return 0;
}

2. 使用动态多态完成上述功能：

#include <iostream>
using namespace std;

class Shape {
public:
    virtual float area() = 0;  // 抽象基类，计算面积
};

class Circle : public Shape {
private:
    float radius;
public:
    Circle(float r) { radius = r; }
    float area() { return 3.14 * radius * radius; }
};

class Square : public Shape {
private:
    float side;
public:
    Square(float s) { side = s; }
    float area() { return side * side; }
};

class Rectangle : public Shape {
private:
    float length, width;
public:
    Rectangle(float l, float w) { length = l; width = w; }
    float area() { return length * width; }
};

class Trapezoid : public Shape {
private:
    float top, bottom, height;
public:
    Trapezoid(float t, float b, float h) { top = t; bottom = b; height = h; }
    float area() { return (top + bottom) * height / 2; }
};

class Triangle : public Shape {
private:
    float base, height;
public:
    Triangle(float b, float h) { base = b; height = h; }
    float area() { return base * height / 2; }
};

int main() {
    Shape *shapes[5];
    shapes[0] = new Circle(5);
    shapes[1] = new Square(4);
    shapes[2] = new Rectangle(3, 5);
    shapes[3] = new Trapezoid(2, 4, 3);
    shapes[4] = new Triangle(3, 4);

    float total_area = 0;
    for (int i = 0; i < 5; i++) {
        total_area += shapes[i]->area();
    }
    cout << "Total area: " << total_area << endl;

    for (int i = 0; i < 5; i++) {
        delete shapes[i];
    }
    return 0;
}

3. 使用派生类构造函数知识完成上述功能：

#include <iostream>
using namespace std;

class Shape {
public:
    virtual float area() = 0;  // 抽象基类，计算面积
};

class Circle : public Shape {
private:
    float radius;
public:
    Circle(float r) { radius = r; }
    float area() { return 3.14 * radius * radius; }
};

class Square : public Shape {
private:
    float side;
public:
    Square(float s) { side = s; }
    float area() { return side * side; }
};

class Rectangle : public Square {
private:
    float width;
public:
    Rectangle(float l, float w) : Square(l) { width = w; }
    float area() { return length * width; }
};

class Trapezoid : public Shape {
private:
    float top, bottom, height;
public:
    Trapezoid(float t, float b, float h) { top = t; bottom = b; height = h; }
    float area() { return (top + bottom) * height / 2; }
};

class Triangle : public Shape {
private:
    float base, height;
public:
    Triangle(float b, float h) { base = b; height = h; }
    float area() { return base * height / 2; }
};

int main() {
    Shape *shapes[5];
    shapes[0] = new Circle(5);
    shapes[1] = new Square(4);
    shapes[2] = new Rectangle(3, 5);
    shapes[3] = new Trapezoid(2, 4, 3);
    shapes[4] = new Triangle(3, 4);

    float total_area = 0;
    for (int i = 0; i < 5; i++) {
        total_area += shapes[i]->area();
    }
    cout << "Total area: " << total_area << endl;

    for (int i = 0; i < 5; i++) {
        delete shapes[i];
    }
    return 0;
}