friend_critter.cpp

来自「the source of dev_c++ most of them for 」· C++ 代码 · 共 53 行

//Friend Critter
//Demonstrates friend functions and operator overloading

#include <iostream>
#include <string>

using namespace std;

class Critter
{
    //make following global functions friends of the Critter class
    friend void Peek(const Critter& aCritter);
    friend ostream& operator<<(ostream& os, const Critter& aCritter);
    
public:
    Critter(const string& name = ""): m_Name(name) {}
     
private:
    string m_Name;
};

void Peek(const Critter& aCritter);
ostream& operator<<(ostream& os, const Critter& aCritter);

int main()
{
    Critter crit("Poochie");

    cout << "Calling Peek() to access crit's private data member, m_Name: \n";
    Peek(crit);
    
    cout << "\nSending crit object to cout with the << operator:\n";
    cout << crit;

    return 0;
}

//global friend function which can access all of a Critter object's members
void Peek(const Critter& aCritter)
{
    cout << aCritter.m_Name << endl;
}

//global friend function which can access all of Critter object's members
//overloads the << operator so you can send a Critter object to cout
ostream& operator<<(ostream& os, const Critter& aCritter)
{
    os << "Critter Object - ";
    os << "m_Name: " << aCritter.m_Name;
    return os;
}