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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