动态内存（初始化和赋值）

#include<iostream>

using namespace std;

class Person
{
char * pName;
public:
Person(char* pN="noName")
{
cout<<"constructing "<<pN<<endl;
pName=new char[strlen(pN)+1];
if(pName)strcpy(pName,pN);
}

Person(const Person& s)//拷贝构造函数
{
cout<<"copy constructing "<<s.pName<<endl;
this->pName=new char[strlen(s.pName)+1];
if(pName)strcpy(pName,s.pName);
}

~Person()
{
cout<<"Destructing "<<pName<<endl;
delete[] pName;
}
Person& operator=(Person& s)
{
cout<<"Assigning "<<s.pName<<endl;
if(this==&s)return s;
delete []pName;//要删除先前的内存空间，不删除会内存泄漏，但是编译器不能找出错误
pName=new char[strlen(s.pName)+1];
if(pName)strcpy(pName,s.pName);
return *this;

}

};
Person functin(const Person& s)
{
return s;
}
void functin2(Person s)
{

}
int main()
{
Person p1("xiao");
Person p2(p1);
Person p3("hai");
Person p4("xieping");
functin(p3);
functin2(p4);
p3=p4;
}