memb_pt.cpp

一本很好的C++学习的丛书！初学者必看的

// memb_pt.cpp -- dereferencing pointers to class members
#include <iostream>
using namespace std;

class Example
{
private:
    int feet;
    int inches;
public:
    Example();
    Example(int ft);
    ~Example();
    void show_in() const;
    void show_ft() const;
    void use_ptr() const;
};

Example::Example()
{
    feet = 0;
    inches = 0;
}

Example::Example(int ft)
{
    feet = ft;
    inches = 12 * feet;
}

Example::~Example()
{
}

void Example::show_in() const
{
    cout << inches << " inches\n";
}

void Example::show_ft() const
{
    cout << feet << " feet\n";
}

void Example::use_ptr() const
{
    Example yard(3);
    int Example::*pt;
    pt = &Example::inches;
    cout << "Set pt to &Example::inches:\n";
    cout << "this->pt: " << this->*pt << endl;
    cout << "yard.*pt: " << yard.*pt << endl;
    pt = &Example::feet;
    cout << "Set pt to &Example::feet:\n";
    cout << "this->pt: " << this->*pt << endl;
    cout << "yard.*pt: " << yard.*pt << endl;
    void (Example::*pf)() const;
    pf = &Example::show_in;
    cout << "Set pf to &Example::show_in:\n";
    cout << "Using (this->*pf)(): ";
    (this->*pf)();
    cout << "Using (yard.*pf)(): ";
    (yard.*pf)();
}

int main()
{
    Example car(15);
    Example van(20);
    Example garage; 

    cout << "car.use_ptr() output:\n";
    car.use_ptr();
    cout << "\nvan.use_ptr() output:\n";
    van.use_ptr();

    return 0;
}