#include "stdafx.h"      #include <iostream>      using namespace std;      class B      {      public:          B():data(0)    //默认构造函数          {               cout << "Default constructor is called." << endl;          }          B(int i):data(i) //带参数的构造函数          {              cout << "Constructor is called." << data << endl;          }          B(B &b)   // 复制（拷贝）构造函数          {              data = b.data; cout << "Copy Constructor is called." << data << endl;          }          B& operator = (const B &b) //赋值运算符的重载          {              this->data = b.data;              cout << "The operator \"= \" is called." << data << endl;              return *this;          }          ~B() //析构函数          {              cout << "Destructor is called. " << data << endl;          }      private:          int data;      };      //函数，参数是一个B类型对象，返回值也是一个B类型的对象      B fun(B b)      {          return b;      }      //测试函数      int _tmain(int argc, _TCHAR* argv[])      {          fun(1);          cout << endl;          B t1 = fun(2);          cout << endl;          B t2;          t2 = fun(3);          return 0;      } 

[b]输出结果为：  [/b]

    Constructor is called.1             //用1构造参数b         Copy Constructor is called.1      //用b拷贝构造一个临时对象，因为此时没有对象来接受fun的返回值         Destructor is called. 1            //参数b被析构         Destructor is called. 1             //临时对象被析构      Constructor is called.2                  //用2构造参数b            Copy Constructor is called.2           //用b拷贝构造t1，此时调用的是拷贝构造函数         Destructor is called. 2                  //参数b被析构      Default constructor is called.             //调用默认的构造函数构造t2            Constructor is called.3                       //用3构造参数b            Copy Constructor is called.3             //用b拷贝构造一个临时对象            Destructor is called. 3                        //参数b被析构            The operator "= " is called.3              //调用=操作符初始化t2，此时调用的是赋值操作符         Destructor is called. 3                         //临时对象被析构            Destructor is called. 3                         //t2被析构            Destructor is called. 2                         //t1被析构            请按任意键继续. . .