Inflearn Community Q&A

<main source>

#include "AutoPtr.h"

#include "Resource.h"

#include <utility> //std::move

#include <vector>

#include <string>

template<class T>

void MySwap(T &a, T &b)

{

T tmp = a;

a = b;

b = tmp;

/*T tmp{ std::move(a) };

a = std::move(b);

b = std::move(tmp);*/

}

int main()

{

using namespace std;

//예제2)

{

AutoPtr<Resource> res1(new Resource(3));

res1.setAll(3);

AutoPtr<Resource> res2(new Resource(5));

res2.setAll(5);

MySwap(res1, res2);

res1->print();

res2->print();

} 

}

***************************************************

<Resource>

#include <iostream>

class Resource

{

//private:

public:

int *m_data = nullptr;

unsigned m_length = 0;

public:

Resource()

{

std::cout << "Resource default constructed" << std::endl;

}

Resource(unsigned length)

{

std::cout << "Resource length constructed" << std::endl;

this->m_data = new int[length];

this->m_length = length;

}

//깊은 복사

Resource(const Resource &res)

{

std::cout << "Resource copy constructed" << std::endl;

Resource(res.m_length); 

for (unsigned i = 0; i < m_length; ++i)

m_data[i] = res.m_data[i];

}

//소멸자

~Resource()

{

std::cout << "Resource destroyed" << std::endl;

if (m_data != nullptr) delete[] m_data;

}

Resource & operator = (Resource &res)

{

std::cout << "Resource copy assignment" << std::endl;

if (&res == this) return *this;

if (this->m_data != nullptr) delete[] m_data;

m_length = res.m_length;

m_data = new int[m_length];

for (unsigned i = 0; i < m_length; ++i)

m_data[i] = res.m_data[i];

return *this;

}

void print()

{

for(unsigned i = 0; i < m_length; ++i)

std::cout << m_data[i] << " ";

std::cout << std::endl;

}

void setAll(const int& v)

{

for (unsigned i = 0; i < m_length; ++i)

m_data[i] = v;

}

};

***************************************************

<Autoptr>

#include <iostream>

template<class T>

class AutoPtr

{

//private:

public:

T *m_ptr;

public:

AutoPtr(T*ptr = nullptr)

:m_ptr(ptr)

{

std::cout << "AutoPtr default constructor" << std::endl;

}

~AutoPtr()

{

std::cout << "AutoPtr destructor" << std::endl;

if (m_ptr != nullptr) delete m_ptr;

}

//copy constructor

AutoPtr(const AutoPtr& a)

{

std::cout << "AutoPtr copy constructor" << std::endl;

//deep copy

m_ptr = new T;

*m_ptr = *a.m_ptr;

}

//copy assignment

AutoPtr& operator = (const AutoPtr& a)

{

std::cout << "AutoPtr copy assignment" << std::endl;

if (&a == this) //prevent self-assignment

return *this;

if (m_ptr != nullptr) delete[] m_ptr;

//deep copy

m_ptr = new T;

*m_ptr = *a.m_ptr;

return *this;

}

//copy constructor나 copy assignment operator을 강제로 사용하지 않게 할 때

//AutoPtr(const AutoPtr& a) = delete;

//AutoPtr& operator=(const AutoPtr& a) = delete;

AutoPtr(AutoPtr&& a)

:m_ptr(a.m_ptr)

{

a.m_ptr = nullptr;

std::cout << "AutoPtr move constructor" << std::endl;

}

AutoPtr& operator=(AutoPtr&& a)

{

std::cout << "AutoPtr move assignment" << std::endl;

if (&a == this) //prevent self-assignment

return *this;

if (!m_ptr) delete m_ptr;

//shallow copy

//모든 것을 다 복사해서 넣는 것이 아니고, 첫 주소를 넣으면 되기 때문에 속도가 빠르다.

m_ptr = a.m_ptr;

a.m_ptr = nullptr;

return *this;

}

T& operator*() const { return *m_ptr; }

};