const修饰虚函数

【1】程序1

 #include <iostream>
 using namespace std;

 class Base
 {
 public:
     virtual void print() const = ;
 };

 class Test : public Base
 {
 public:
     void print();
 };

 void Test::print()
 {
     cout << "Test::print()" << endl;
 }

 void main()
 {
     // Base* pChild = new Test(); //compile error!
     // pChild->print();
 }

【2】程序2

 #include <iostream>
 using namespace std;

 class Base
 {
 public:
     virtual void print() const = ;
 };

 class Test : public Base
 {
 public:
     void print();
     void print() const;
 };

 void Test::print()
 {
     cout << "Test::print()" << endl;
 }

 void Test::print() const
 {
     cout << "Test::print() const" << endl;
 }

 void main()
 {
     Base* pChild = new Test();
     pChild->print();
 }
 /*
 Test::print() const
 */

【3】程序3

 #include <iostream>
 using namespace std;

 class Base
 {
 public:
     virtual void print() const = ;
 };

 class Test : public Base
 {
 public:
     void print();
     void print() const;
 };

 void Test::print()
 {
     cout << "Test::print()" << endl;
 }

 void Test::print() const
 {
     cout << "Test::print() const" << endl;
 }

 void main()
 {
     Base* pChild = new Test();
     pChild->print();

     const Test  obj;
     obj.print();

     Test obj1;
     obj1.print();

     Test* pOwn = new Test();
     pOwn->print();
 }

 /*
 Test::print() const
 Test::print() const
 Test::print()
 Test::print()
 */

备注：一切皆在代码中。

总结：const修饰成员函数，也属于函数重载的一种范畴。

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