copy_constructor 复制构造函数1

#include<iostream>

#include<string.h>

using namespace std;

class name{

public:

name(char *pn);

~name();

name::name(const name& n);

protected:

char *pname;

int size;

};

name::name(char *pn){

cout << "constructing" << pn << endl;

pname = new char[strlen(pn) + 1];

if (pname != 0)

strcpy_s(pname, strlen(pn) + 1, pn);

size = strlen(pn);

}

name::~name(){

cout << "Destructing" << pname << endl;

pname[0] = '\0';

delete[]pname;

size = 0;

}

name::name(const name& n){//拷贝构造函数。

cout << "call copy_constructor" << endl;

int size = n.size+1;

pname = new char[size ];//为其临时对象申请个内存。让临时对象的指针指向它。

//防止释放临时对象时把原来的对象的指针所指空间给弄乱

strcpy_s(pname, size,n.pname);//两个参数不好办，用三个参数。

}

void main(){

name Obj1("NoName");

cout << "strlen(\"NoName\")=" << strlen("NoName") << endl;

name Obj2 = Obj1;

system("pause");

}