C++繼承可以是單一繼承或多重繼承，每一個繼承連接可以是public,protected,private也可以是virtual或non-virtual。然后是各個成員函數選項可以是virtual或non-virtual或pure virtual。本文僅僅作出一些關鍵點的驗證。
public繼承，例如下：
1 class base
2 ｛...｝
3 class derived:public base
4 ｛...｝
如果這樣寫，編譯器會理解成類型為derived的對象同時也是類型為base的對象，但類型為base的對象不是類型為derived的對象。這點很重要。那么函數形參為base類型適用于derived，形參為derived不適用于base。下面是驗證代碼，一個參數為base的函數，傳入derived應該成功執行，相反，一個參數為derived的函數
#include <iostream>#include <stdio.h>class base{ public: base() :baseName(""),baseData(0) {} base(std::string bn,int bd) :baseName(bn),baseData(bd) {} std::string getBaseName() const { return baseName; } int getBaseData()const { return baseData; } private: std::string baseName; int baseData;};class derived:public base{ public: derived():base(),derivedName("") {} derived(std::string bn,int bd,std::string dn) :base(bn,bd),derivedName(dn) {} std::string getDerivedName() const { return derivedName; } private: std::string derivedName;};void show(std::string& info,const base& b){ info.append("Name is "); info.append(b.getBaseName()); info.append(", baseData is "); char buffer[10]; sprintf(buffer,"%d",b.getBaseData()); info.append(buffer);}int main(int argc,char* argv[]){ base b("test",10); std::string s; show(s,b); std::cout<<s<<std::endl; derived d("btest",5,"dtest"); std::string ss; show(ss,d); std::cout<<ss<<std::endl; return 0;}運行結果為：
base:baseName is test, baseData is 10
base:baseName is btest, baseData is 5
下面改改代碼，將函數參數變為derived
void show2(std::string& info,const derived& d){ info.append("Name is "); info.append(d.getBaseName()); info.append(", baseData is "); char buffer[10]; sprintf(buffer,"%d",d.getBaseData()); info.append(buffer);}調用show(ss,d);編譯器報錯
1 derived_class.cpp: In function `int main(int, char**)':2 derived_class.cpp:84: error: invalid initialization of reference of type 'const derived&' from expression of type 'base'3 derived_class.cpp:70: error: in passing argument 2 of `void show2(std::string&, const derived&)'
第二點對各種形式的繼承作出驗證，首先給出表格
| 繼承方式/成員類型 | public | protected | private |
| public | public | protected | 無法繼承 |
| protected | protected | protected | 無法繼承 |
| private | private | private | 無法繼承 |
這里解釋一下，這里僅僅表達基類的成員，被public,protected,private三種方式繼承后，在原基類為public,protectedc,private的成員在繼承類里類型為表格里內容
class base{ public: std::string testPublic() { return std::string("this is public base"); } protected: std::string testProtected() { return std::string("this is protected base"); } private: std::string testPrivate() { return std::string("this is private base"); }};class derivedPublic:public base{ public: std::string testPubPublic() { return testPublic()+= "in derived"; } std::string testProPublic() { return testProtected()+= "in derived"; } std::string testPriPublic() { return testPrivate()+= "in derived"; }};int main(int argc,char* argv[])｛ derivedPublic dpub; std::cout << dpub.testPublic() << std::endl; ｝報下面錯誤，說明testPrivate()不是derived私有函數而是base的私有函數
derived11.cpp:16: error: `std::string base::testPrivate()' is privatederived11.cpp:36: error: within this context
這樣驗證private類型成員無法被繼承（public,private,protected）注：private，protected略去不做證明
下面只要驗證 testProtected 能被第三層繼承類繼承，但是無法被第三層類直接調用就說明是public繼承后繼承類型為protected，而基類為Public類型成員則即可被繼承又可以直接調用。
#include <iostream>#include <string>class base{ public: std::string testPublic() { return std::string("this is public base"); } protected: std::string testProtected() { return std::string("this is protected base"); } private: std::string testPrivate() { return std::string("this is private base"); }};class derivedPublic:public base{ public: std::string testPubPublic() { return testPublic()+= "in derived"; } std::string testProPublic() { return testProtected()+= "in derived"; } // std::string testPriPublic() // { // return testPrivate()+= "in derived";// }};class deepDerived:public derivedPublic{ public: std::string deepProtected() { return testProtected() +="in deep"; } std::string deepPublic() { return testPublic() +="indeep"; }};int main(int argc,char* argv[]){ derivedPublic dpub; std::cout << dpub.testProtected() << std::endl; deepDerived deepdpub; std::cout<<deepdpub.testPublic() <<std::endl; std::cout<<deepdpub.testProtected() <<std::endl; std::cout<<deepdpub.deepProtected() <<std::endl; std::cout<<deepdpub.deepPublic() <<std::endl;}這里服務器報錯
derived12.cpp:13: error: `std::string base::testProtected()' is protectedderived12.cpp:62: error: within this context
這樣就驗證了一個是public，一個是protected，protected是不能直接調用的，但是被繼承后是可以被public成員調用的。
下面的已經證明，詳細步驟就略去如果對該部分驗證感興趣，可以看下面代碼。
#include <iostream>#include <string>class base{ public: std::string testPublic() { return std::string("this is public base"); } protected: std::string testProtected() { return std::string("this is protected base"); } private: std::string testPrivate() { return std::string("this is private base"); }};class derivedPublic:public base{ public: std::string testPubPublic() { return testPublic()+= "in derived"; } std::string testProPublic() { return testProtected()+= "in derived"; } // std::string testPriPublic() //私有成員并沒有被繼承下來// { // return testPrivate()+= "in derived";// }};class deepDerived:public derivedPublic{ public: std::string test() { return testPublic() +="in 3"; }};class derivedProtected:protected base{ public: std::string testPubProtected() { return testPublic()+= "in derived"; } std::string testProProtected() { return testProtected()+= "in derived"; }};class deepDerived2:public derivedProtected{ public: std::string test() { return testPublic() +="in 3"; }};class derivedPrivate:private base{ public: std::string testPubPirvate() { return testPublic()+= "in derived"; } std::string testProPrivate() { return testProtected()+= "in derived"; } };//class deepDerived3:public derivedPrivate//{// public:// std::string test()// {// return testPublic() +="in 3";// }//};int main(int argc,char* argv[]){ derivedPublic dpub; //derivedProtected dpro; //derivedPrivate dpri; std::cout<<dpub.testPublic()<<std::endl; // //std::cout<<dpub.testProtected()<<std::endl; //用戶被繼承也是無法使用 //cout<<dpub.testPrivate()<<std::endl; //基類都是私有函數 std::cout<<dpub.testPubPublic()<<std::endl; std::cout<<dpub.testProPublic()<<std::endl; //std::cout<<dpub.testPriPrivate()<<std::endl; //沒有被繼承 deepDerived dd; std::cout<<dd.test()<<std::endl; derivedProtected dpro; //std::cout<<dpro.testPublic()<<std::endl; //變成protected類型 std::cout<<dpro.testPubProtected()<<std::endl; std::cout<<dpro.testProProtected()<<std::endl; deepDerived2 dd2; std::cout<<dd2.test()<<std::endl; derivedPrivate dpri; std::cout<<dpri.testPubPirvate()<<std::endl; std::cout<<dpri.testProPrivate()<<std::endl; // deepDerived3 dd3;// std::cout<<dd3.test()<<std::endl;｝以上就是對C++ j繼承的資料整理，后續繼續補充相關資料，謝謝大家對本站的支持！
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