cpp
复制代码
#include <iostream>
#include <list>
using namespace std;
class Visitor;
// 组成Computer的各组件基类
class Element
{
public:
Element(string strName) : m_strName(strName) {}
string GetName()
{
return m_strName;
}
// 组件接受访问者访问的接口
virtual void AcceptVisitor(Visitor *pVisitor) = 0;
private:
// 组件的标识名称
string m_strName;
};
// 访问者基类,针对不同组件,提供不同的访问接口
class Visitor
{
public:
virtual void VisitCPU(Element *pEle) = 0;
virtual void VisitGPU(Element *pEle) = 0;
virtual void VisitDISK(Element *pEle) = 0;
};
// Computer类,由各组件组成,访问者访问Computer时将依次访问各组件
class Computer
{
public:
~Computer()
{
for (Element *pElement : m_listEle)
{
delete pElement;
}
}
void AddElement(Element *pEle)
{
m_listEle.push_back(pEle);
}
void DelElement(Element *pEle)
{
m_listEle.remove(pEle);
}
// 访问者访问Computer时将依次访问各组件
void AcceptVisitor(Visitor *pVisitor)
{
for (Element *pElement : m_listEle)
{
pElement->AcceptVisitor(pVisitor);
}
}
private:
list<Element *> m_listEle;
};
// 访问者实现类,实现各自的访问方法
class VisitorA : public Visitor
{
public:
void VisitCPU(Element *pEle)
{
printf("Visitor A record CPU's name:%s\n", pEle->GetName().c_str());
}
void VisitGPU(Element *pEle)
{
printf("Visitor A do nothing to GPU:%s\n", pEle->GetName().c_str());
}
void VisitDISK(Element *pEle)
{
printf("Visitor A change DISK:%s\n", pEle->GetName().c_str());
}
};
class VisitorB : public Visitor
{
public:
void VisitCPU(Element *pEle)
{
printf("Visitor B do nothing to CPU:%s\n", pEle->GetName().c_str());
}
void VisitGPU(Element *pEle)
{
printf("Visitor B record GPU's name:%s\n", pEle->GetName().c_str());
}
void VisitDISK(Element *pEle)
{
printf("Visitor B do nothing to DISK:%s\n", pEle->GetName().c_str());
}
};
// 组件的实现类,调用访问者相应的访问方法
class CPU : public Element
{
public:
CPU(string strName) : Element(strName) {}
void AcceptVisitor(Visitor *pVisitor)
{
pVisitor->VisitCPU(this);
}
};
class GPU : public Element
{
public:
GPU(string strName) : Element(strName) {}
void AcceptVisitor(Visitor *pVisitor)
{
pVisitor->VisitGPU(this);
}
};
class Disk : public Element
{
public:
Disk(string strName) : Element(strName) {}
void AcceptVisitor(Visitor *pVisitor)
{
pVisitor->VisitDISK(this);
}
};
int main()
{
Computer oComputer;
oComputer.AddElement(new CPU("i9-10980XE"));
oComputer.AddElement(new GPU("Titan RTX"));
oComputer.AddElement(new Disk("HOF PRO M.2"));
VisitorA oVisitorA;
VisitorB oVisitorB;
oComputer.AcceptVisitor(&oVisitorA);
oComputer.AcceptVisitor(&oVisitorB);
return 0;
}
c
复制代码
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Element Element;
typedef struct Visitor Visitor;
typedef struct Computer Computer;
typedef struct CPU CPU;
typedef struct GPU GPU;
typedef struct Disk Disk;
// 组件基类
struct Element
{
char *m_strName;
void (*accept)(struct Element *, struct Visitor *);
};
// 访问者基类
struct Visitor
{
void (*visitCPU)(struct Element *);
void (*visitGPU)(struct Element *);
void (*visitDisk)(struct Element *);
};
// Computer类
struct Computer
{
struct Element **m_listEle;
size_t m_listSize;
size_t m_listCapacity;
};
// CPU类
struct CPU
{
struct Element base;
};
// GPU类
struct GPU
{
struct Element base;
};
// Disk类
struct Disk
{
struct Element base;
};
// 创建组件
struct Element *createElement(const char *name, void (*accept)(struct Element *, struct Visitor *))
{
struct Element *element = malloc(sizeof(struct Element));
element->m_strName = strdup(name);
element->accept = accept;
return element;
}
// 创建访问者
struct Visitor *createVisitor(void (*visitCPU)(struct Element *),
void (*visitGPU)(struct Element *),
void (*visitDisk)(struct Element *))
{
struct Visitor *visitor = malloc(sizeof(struct Visitor));
visitor->visitCPU = visitCPU;
visitor->visitGPU = visitGPU;
visitor->visitDisk = visitDisk;
return visitor;
}
// 创建Computer
struct Computer *createComputer()
{
struct Computer *computer = malloc(sizeof(struct Computer));
computer->m_listEle = NULL;
computer->m_listSize = 0;
computer->m_listCapacity = 0;
return computer;
}
// 添加组件到Computer
void addElement(struct Computer *computer, struct Element *element)
{
if (computer->m_listSize >= computer->m_listCapacity)
{
size_t newCapacity = computer->m_listCapacity == 0 ? 1 : computer->m_listCapacity * 2;
computer->m_listEle = realloc(computer->m_listEle, newCapacity * sizeof(struct Element *));
computer->m_listCapacity = newCapacity;
}
computer->m_listEle[computer->m_listSize++] = element;
}
// 删除组件
void delElement(struct Computer *computer, struct Element *element)
{
size_t i;
for (i = 0; i < computer->m_listSize; i++)
{
if (computer->m_listEle[i] == element)
{
memmove(&computer->m_listEle[i], &computer->m_listEle[i + 1], (computer->m_listSize - i - 1) * sizeof(struct Element *));
computer->m_listEle[--computer->m_listSize] = NULL;
break;
}
}
}
// 访问者访问Computer
void acceptVisitor(struct Computer *computer, struct Visitor *visitor)
{
size_t i;
for (i = 0; i < computer->m_listSize; i++)
{
computer->m_listEle[i]->accept(computer->m_listEle[i], visitor);
}
}
// 清理Computer
void clearComputer(struct Computer *computer)
{
size_t i;
for (i = 0; i < computer->m_listSize; i++)
{
free(computer->m_listEle[i]->m_strName);
free(computer->m_listEle[i]);
}
free(computer->m_listEle);
free(computer);
}
// 访问者A实现
void visitorAVisitCPU(struct Element *ele)
{
printf("Visitor A record CPU's name:%s\n", ele->m_strName);
}
void visitorAVisitGPU(struct Element *ele)
{
printf("Visitor A do nothing to GPU:%s\n", ele->m_strName);
}
void visitorAVisitDisk(struct Element *ele)
{
printf("Visitor A change DISK:%s\n", ele->m_strName);
}
// 访问者B实现
void visitorBVisitCPU(struct Element *ele)
{
printf("Visitor B do nothing to CPU:%s\n", ele->m_strName);
}
void visitorBVisitGPU(struct Element *ele)
{
printf("Visitor B record GPU's name:%s\n", ele->m_strName);
}
void visitorBVisitDisk(struct Element *ele)
{
printf("Visitor B do nothing to DISK:%s\n", ele->m_strName);
}
int main()
{
struct Computer *oComputer = createComputer();
addElement(oComputer, createElement("i9-10980XE", visitorAVisitCPU));
addElement(oComputer, createElement("Titan RTX", visitorAVisitGPU));
addElement(oComputer, createElement("HOF PRO M.2", visitorAVisitDisk));
struct Visitor *oVisitorA = createVisitor(visitorAVisitCPU, visitorAVisitGPU, visitorAVisitDisk);
struct Visitor *oVisitorB = createVisitor(visitorBVisitCPU, visitorBVisitGPU, visitorBVisitDisk);
acceptVisitor(oComputer, oVisitorA);
acceptVisitor(oComputer, oVisitorB);
clearComputer(oComputer);
free(oVisitorA);
free(oVisitorB);
return 0;
}