C++ 中const修饰虚函数实例详解

C++ 中const修饰虚函数实例详解

【1】程序1


#include <iostream>
using namespace std;

class Base
{
public:
 virtual void print() const = 0;
};

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 = 0;
};

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 = 0;
};

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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