C++——多态经典案例（一）组装电脑

案例：小明打算买两台组装电脑，假设电脑零部件包括CPU、GPU和内存组成。
一台电脑使用intel的CPU、GPU和内存条
一台电脑使用Huawei的CPU、GPU和Intel的内存条

分析：使用多态进行实现
将CPU、GPU和内存条定义为抽象类，内部分别定义其对应功能的纯虚函数
Intel的CPU继承CPU，并实现其内部的纯虚函数（calculate）
Intel的GPU继承GPU，并实现其内部的纯虚函数（display）
Intel的MEMORY继承MEMORY，并实现其内部的纯虚函数（memory）
同样华为也一样继承CPU、GPU和MEMORY并实现对应的纯虚函数

封装一个Computer类，包含CPU、GPU和MEMORY，其成员属性为CPU、GPU和MEMORY的指针
内部有个work方法，用于调用CPU、GPU和MEMORY对应的方法

最后小明通过Computer类进行组装自己的电脑，并运行

#include<iostream>
class CPU 
{
public:virtual void calculate() = 0;
};class GPU
{
public:virtual void display() = 0;
};class MEMORY
{
public:virtual void memory() = 0;
};class Computer 
{
public:Computer(CPU *cpu,GPU *gpu,MEMORY *memory){m_cpu = cpu;m_gpu = gpu;m_memory = memory;}void work() {m_cpu->calculate();m_gpu->display();m_memory->memory();}~Computer(){if (m_cpu != NULL) {delete m_cpu;m_cpu = NULL;}if (m_gpu != NULL){delete m_gpu;m_gpu = NULL;}if (m_memory != NULL){delete m_memory;m_memory = NULL;}}private:CPU *m_cpu;GPU *m_gpu;MEMORY *m_memory;
};class IntelCPU :public CPU
{
public:virtual void calculate(){std::cout << "IntelCPU is calculate..." << std::endl;}
};
class IntelGPU :public GPU
{
public:virtual void display(){std::cout << "IntelGPU is display..." << std::endl;}
};
class IntelMEMORY :public MEMORY
{
public:virtual void memory(){std::cout << "IntelMEMORY is memory..." << std::endl;}
};class HuaweiCPU :public CPU
{
public:virtual void calculate(){std::cout << "HuaweiCPU is calculate..." << std::endl;}
};
class HuaweiGPU :public GPU
{
public:virtual void display(){std::cout << "HuaweiGPU is display..." << std::endl;}
};
class HuaweiMEMORY :public MEMORY
{
public:virtual void memory(){std::cout << "HuaweiMEMORY is memory..." << std::endl;}
};int main(int argc,char **argv) 
{CPU *my_CPU = new IntelCPU;GPU *my_GPU = new IntelGPU;MEMORY *my_memory = new IntelMEMORY;Computer *my_computer = new Computer(my_CPU, my_GPU, my_memory);my_computer->work();delete my_computer;Computer* my_computer_2 = new Computer(new HuaweiCPU,new HuaweiGPU,new IntelMEMORY);my_computer_2->work();return 0;
}

运行效果：