试验C++构造函数，析构函数，拷贝构造函数和赋值构造函数 

#include "stdafx.h"

#include <iostream>

#include <string.h>

using namespace std;

class student

{

public:

 student()

 {

  cout<<"default constructor is called!"<<endl;

  name=new char[1];

  name[0]='\0';

  age=0;

 }

 student(char* name,int age)

 {

  if(name==NULL)

  {

   this->name=new char[1];

   name[0]='\0';

  }

  else

  {

   this->name=new char[strlen(name)+1];

   strcpy(this->name,name);

   cout<<"constructing student:"<<this->name<<endl;

   this->age=age;

  }

 }

 student(const student& stu)

 {

  this->name=new char[strlen(stu.name)+strlen("copy of")+1];

  strcpy(this->name,stu.name);

  strcat(this->name,"copy of");

  cout<<"constructing student:"<<this->name<<endl;

  this->age=stu.age;

  

 }

 student& operator=(const student& stu)

 {

  if(this==&stu)  //检查自赋值用指针比较，不能用对象比较，对象比较函数未定义

   return *this;

  if(this->name)

   delete this->name;

  this->name=new char[strlen(stu.name)+strlen("===construct")+1];

  strcat(stu.name,"===construct");

  strcpy(this->name,stu.name);

  cout<<"constructing student by ====!"<<endl;

  this->age=stu.age;

  return *this;

 }

 ~student()

 {

  cout<<"destructing student:"<<this->name<<"age:"<<this->age<<endl;

  if(this->name)

   delete this->name;

  this->name=NULL;

 }

private:

 char* name;

 int age;

};

student test(student s)     //实参传递给形参的时候调用拷贝构造函数

{

 cout<<"in the test function!"<<endl;

 student s2("temp",22);

 //返回临时对象前先拷贝构造一个临时对象，然后复制给实参

 //返回栈空间，程序本身有问题。但是拷贝构造函数将原来的对象在一个新空间构造，

 //所以不存在内存泄露。

 return s2; //好像编译器调用析构函数去析构自己产生的临时对象出错

}

int main(int argc, char* argv[])

{

 cout<<"start the programing!"<<endl;

 student stu("roger",11);

 cout<<"to execute the test()!"<<endl;

 //int i=0;

 //while(i++<10000000)

 student s3("gugy",23);

 s3=test(stu);   //调用赋值函数

 cout<<"exit the programing!"<<endl;

 return 0;

}