<code class="lang-cpp">MyClass &operator=(const MyClass& src) {
                                                            cout << "operator=" << endl;
    Dispose(); // 【不能处理自赋值情况】
    CopyFrom(src);
    return *this;
}</code></pre><pre data-tag="nkcsource" data-type="pre"><code class="lang-cpp">// MyRefClass.cpp : 定义控制台应用程序的入口点。
//
               
#include "stdafx.h"
               
#include <string.h>
#include <stdio.h>
#include <iostream>
using namespace std;
               
class MyClass { // 引用类的写法
private:
    void CopyFrom(const MyClass& src) {
                                                                cout << "copyfrom" << endl;
        if (src.pm_obj != NULL)
        {
            src.pm_obj->m_refcount++; // 当复制时增加计数并引用源对象
            this->pm_obj = src.pm_obj;
        }
    }
    void Dispose() {
                                                                cout << "dispose" << endl;
        if (this->pm_obj != NULL)
        {
            if (--this->pm_obj->m_refcount <=0) 当析构时减少计数             {                 disposedata(); 若计数减少到零则销毁对象                 delete this->pm_obj;
                this->pm_obj = NULL;
            }
        }
    }
                   
    // TODO: 真正的初始化函数（自己写）
    void InitData(char *str1){
                                                                cout << "initdata" << endl;
        this->pm_obj->resource = new char [strlen(str1)+20];
        strcpy(this->pm_obj->resource, str1);
    }
    // TODO: 真正的析构函数（自己写）
    void DisposeData() {
                                                                cout << "disposedata" << endl;
        delete [] this->pm_obj->resource;
        this->pm_obj->resource = NULL;
    }
               
public:
    // Big-3 的固定写法，不用解释
    MyClass &operator=(const MyClass& src) {
                                                                cout << "operator=" << endl;
        if (&src != this) { // 【更改】不是自赋值的话
            Dispose();
            CopyFrom(src);
        }
        return *this;
    }
    MyClass(const MyClass& src) {
                                                                cout << "copy" << endl;
        CopyFrom(src);
    }
    ~MyClass() {
                                                                cout << "delete" << endl;
        Dispose();
    }
    // 构造函数写法
    MyClass() {
                                                                cout << "new()" << endl;
        this->pm_obj = new MyClassBase; // 新建对象并将计数置为1
        this->pm_obj->m_refcount = 1;
        InitData("");
    }
    MyClass(char *str1) {
                                                                cout << "new(str)" << endl;
        this->pm_obj = new MyClassBase; // 新建对象并将计数置为1
        this->pm_obj->m_refcount = 1;
        InitData(str1);
    }
               
    // Dup函数（传统复制函数）可以不写
    MyClass Dup() {
                                                                cout << "dup" << endl;
        MyClass temp(this->pm_obj->resource); // 新建一个完全独立的对象并返回
        return temp;
    }
               
    // TODO: 此处添加其它成员函数以方便调用
    char *GetString() {
        return this->pm_obj->resource;
    }
               
    void *GetData() {
        return this->pm_obj;
    }
               
    int GetCount() {
        return this->pm_obj->m_refcount;
    }
               
private:
    // 引用类的变量仅此一份
    struct MyClassBase{
        int m_refcount;
               
        // TODO: 此处添加常规变量以方便保存状态
        char *resource;
               
    } *pm_obj;
};
               
               
int _tmain(int argc, _TCHAR* argv[])
{
    // 测试程序
    MyClass a;
    MyClass b = a;
    MyClass c;
    c = b;
    MyClass d=b.Dup();
    printf("%p %p %p %p\n",a.GetData(), b.GetData(), c.GetData(), d.GetData());
    printf("%p %p %p %p\n",a.GetString(), b.GetString(), c.GetString(), d.GetString());
    printf("%d %d %d %d\n",a.GetCount(), b.GetCount(), c.GetCount(), d.GetCount());
    return 0;
}</=0)></iostream></stdio.h></string.h></code></code>