构建一个车（vehicle）基类，包含Run、Stop两个纯虚函数。由此基类，派生出（Car）轿车类，（truck）卡车类，在这两个类中别分定义Run和Stop两个函数，每个函数中输出 car 或者 truck is running 或 stopping。主函数中，分别实例化轿车类与卡车类，并构建基类指针，分别调用两个派生类对象的Run和Stop函数。

好的，下面是代码实现：

#include<iostream>
using namespace std;

class Vehicle {
public:
    virtual void Run() = 0;
    virtual void Stop() = 0;
};

class Car : public Vehicle {
public:
    virtual void Run() {
        cout << "Car is running." << endl;
    }
    virtual void Stop() {
        cout << "Car is stopping." << endl;
    }
};

class Truck : public Vehicle {
public:
    virtual void Run() {
        cout << "Truck is running." << endl;
    }
    virtual void Stop() {
        cout << "Truck is stopping." << endl;
    }
};

int main() {
    Car car;
    Truck truck;

    Vehicle* p = &car;
    p->Run();
    p->Stop();

    p = &truck;
    p->Run();
    p->Stop();

    return 0;
}

输出结果为：

Car is running.
Car is stopping.
Truck is running.
Truck is stopping.

希望这个例子能帮助你理解如何使用 C++ 的纯虚函数和类的继承。