深度剖析C++語言特點(diǎn)
C++作為一種語言,大多數(shù)的人都是把它默認(rèn)為面向?qū)ο蟮闹С?,認(rèn)為他就是C語言的替代品,一種延伸而已,而事際上,C++與C是完全不同的語言。用過C++語言的朋友都覺得C++語言的確是個(gè)好語言。
但有時(shí)由于特殊需要,不得不用C++,在C++中要想實(shí)現(xiàn)C#中的Thread等也是可行的,不過代碼要稍復(fù)雜:
- //delegate 0
- #define DEFINE_DELEGATE(NAME, R)\
- class NAME##Delegate\
- {\
- public:\
- virtual ~NAME##Delegate(void){ }\
- virtual R operator()(void) = 0;\
- };\
- template\
- class NAME##DelegateImpl : public NAME##Delegate\
- {\
- private:\
- typedef R (C::*F)(void);\
- C* m_class;\
- F m_fun;\
- public:\
- NAME##DelegateImpl(C* c, F f){ m_class = c; m_fun = f; }\
- virtual R operator()(void)\
- {\
- if(m_class)\
- return (m_class-*m_fun)();\
- }\
- };\
- template\
- NAME##Delegate* Make##NAME##Delegate(C* c, F f)\
- {\
- return new NAME##DelegateImpl(c, f);\
- }
- //////////////////////////////////////////////////////////////////////////
- //delegate 1
- #define DEFINE_DELEGATE(NAME, R, P1)\
- class NAME##Delegate\
- {\
- public:\
- virtual ~NAME##Delegate(void){ }\
- virtual R operator()(P1 p1) = 0;\
- };\
- template\
- class NAME##DelegateImpl : public NAME##Delegate\
- {\
- private:\
- typedef R (C::*F)(P1);\
- C* m_class;\
- F m_fun;\
- public:\
- NAME##DelegateImpl(C* c, F f){ m_class = c; m_fun = f; }\
- virtual R operator()(P1 p1)\
- {\
- if(m_class)\
- return (m_class-*m_fun)(p1);\
- }\
- };\
- template\
- NAME##Delegate* Make##NAME##Delegate(C* c, F f)\
- {\
- return new NAME##DelegateImpl(c, f);\
- }
這個(gè)例子比較簡(jiǎn)單C++語言用來實(shí)現(xiàn)某個(gè)功能,client是客戶程序,要想在m_sdk做處理的時(shí)候能發(fā)送通知到client,有幾個(gè)方法可以實(shí)現(xiàn)。其一是發(fā)線程消息,其一是回調(diào),但傳統(tǒng)的回調(diào)對(duì)面向?qū)ο蟮闹С植⒉缓?,這就是實(shí)現(xiàn)delegate的出發(fā)點(diǎn)。 下面是一個(gè)實(shí)現(xiàn): class Delegate
- DEFINE_DELEGATE(Open, void, int, string)
- class sdk
- {
- public:
- OpenDelegate* pEvent;
- sdk(): pEvent(NULL) { }
- void Open()
- {
- cout
- if(pEvent != NULL)
- (*pEvent)(100, "你好");
- }
- };
- class client
- {
- private:
- sdk m_sdk;
- public:
- client()
- {
- m_sdk.pEvent = MakeOpenDelegate(this, OnOpen2);
- }
- void Open()
- {
- m_sdk.Open();
- }
- void OnOpen()
- {
- cout
- }
- void OnOpen2(int t, string str)
- {
- cout
- }
- };
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