クラスのコンストラクション関数

//  strcpy , 
#define _CRT_SECURE_NO_WARNINGS

#include <iostream>
#include <stdint.h>
using namespace std;

class MyClass
{
public:
	MyClass();
	~MyClass();
	void foo(){cout << "A" << endl;}
private:

};

MyClass::MyClass()
{
}

inline MyClass::~MyClass()//  
{
	cout << "inline destructed." << endl;
}

class StringT
{
public:
	StringT(const char *str = NULL);           //  
	StringT(const StringT &other);             //  
	StringT & operator=(const StringT &other); //  
	void Print(const StringT &other) const;    // const 
	~StringT(void);                            //  

private:
	char *m_pdata;
};

StringT::~StringT(void)
{
	delete m_pdata;
}

void StringT::Print(const StringT &other) const
{
	int len = strlen(other.m_pdata);
	char *p = other.m_pdata;
	for (int i = 0; i < len; i++)
	{
		cout << *(p++);
	}
	cout << endl;
}

StringT::StringT(const char *str)
{
	if (str == NULL)
	{
		m_pdata = new char[1];
		*m_pdata = '\0';
	} 
	else
	{
		int length = strlen(str);
		m_pdata = new char[length + 1];
		strcpy(m_pdata,str);
	}
}
StringT::StringT(const StringT & other)
{
	if (other.m_pdata == NULL)
	{
		m_pdata = new char[1];
		*m_pdata = '\0';
	} 
	else
	{
		int length = strlen(other.m_pdata);
		m_pdata = new char[length + 1];
		strcpy(m_pdata,other.m_pdata);
	}
}
// ①
StringT& StringT::operator =(const StringT &other)
{
	// 1 
	if (this == &other)
	{
		return *this;
	}
	// 2 
	delete m_pdata;

	// 3 ， other 
	int length = strlen(other.m_pdata);
	m_pdata = new char[length + 1];
	strcpy(m_pdata, other.m_pdata);
	return *this;
}
// ②  offer 1
//StringT& StringT::operator =(const StringT &other)
//{
//	if (this != &other)
//	{
//		StringT strTmp(other);
//		char *pTmp = strTmp.m_pdata;
//		strTmp.m_pdata = m_pdata;
//		m_pdata = pTmp;
//	}
//	return *this;
//}
int main()
{
	MyClass *P = new MyClass();
	P->foo();
	delete P;

	StringT str("hello");
	StringT s(str);
	StringT t = s;

	cout << "str = ";
	str.Print(str);

	cout << "s = ";
	s.Print(s);

	cout << "t = ";
	t.Print(t);

	return 0;
}