10;//右值
	int a = 10;//a是左值
	add(2, 3);//右值
	x+y;//右值
	const int a;//左值

	int a = 10;
	int& d = a;//左值引用
	int&& e = 10;//右值引用
	int&& f = a + 1;
	int&& c = add(2, 3);

	int&& c = a;//右值引用不能給左值取別名
	int& d = add(3, 4);//左值引用不能給右值取別名
	int&& e = move(a);//當(dāng)對左值加move的時候可以
	const int& f = add(3, 4);//當(dāng)對引用加const后可以取別名

	int&& a = 10;
	a=20;
	cout<<&a<<endl;
	//int&& b = a;//錯誤

namespace my_string
{
	class string
	{
	public:
		typedef char* iterator;
		iterator begin()
		{
			return _str;
		}
		iterator end()
		{
			return _str + _size;
		}
		//構(gòu)造函數(shù)
		string(const char* str = "")
			:_size(strlen(str))
			, _capacity(_size)
		{
			cout << "string(char* str)" << endl;

			_str = new char[_capacity + 1];
			strcpy(_str, str);
		}
		// s1.swap(s2)
		void swap(string& s)
		{
			::swap(_str, s._str);
			::swap(_size, s._size);
			::swap(_capacity, s._capacity);
		}
		// 拷貝構(gòu)造
		string(const string& s)
			:_str(nullptr)
			, _size(0)
			, _capacity(0)
		{
			cout << "string(const string& s) -- 深拷貝" << endl;
			string tmp(s._str);
			swap(tmp);
		}
		// 移動構(gòu)造
		string(string&& s)
			:_str(nullptr)
			, _size(0)
			, _capacity(0)
		{
			cout << "string(string&& s) -- 資源轉(zhuǎn)移" << endl;
			this->swap(s);
		}
		// 移動賦值
		string& operator=(string&& s)
		{
			cout << "string& operator=(string&& s) -- 轉(zhuǎn)移資源" << endl;
			swap(s);
			return *this;
		}
		//賦值
		string& operator=(const string& s)
		{
			cout << "string& operator=(string s) -- 深拷貝" << endl;
			string tmp(s);
			swap(tmp);
			return *this;
		}
		~string()
		{
			delete[] _str;
			_str = nullptr;
		}
		//下標(biāo)訪問
		char& operator[](size_t pos)
		{
			assert(pos < _size);
			return _str[pos];
		}
		//調(diào)換順序
		void reserve(size_t n)
		{
			if (n > _capacity)
			{
				char* tmp = new char[n + 1];
				strcpy(tmp, _str);
				delete[] _str;
				_str = tmp;

				_capacity = n;
			}
		}
		//插入
		void push_back(char ch)
		{
			if (_size >= _capacity)
			{
				size_t newcapacity = _capacity == 0 ? 4 : _capacity * 2;
				reserve(newcapacity);
			}
			_str[_size] = ch;
			++_size;
			_str[_size] = '\0';
		}
		//string operator+=(char ch)
		string& operator+=(char ch)
		{
			push_back(ch);
			return *this;
		}
		string operator+(char ch)
		{
			string tmp(*this);
			push_back(ch);

			return tmp;
		}
		const char* c_str() const
		{
			return _str;
		}
	private:
		char* _str;
		size_t _size;
		size_t _capacity; // 不包含最后做標(biāo)識的\0
	};
	my_string::string to_string(int value)
	{
		my_string::string str;
		while (value)
		{
			int val = value % 10;
			str += ('0' + val);
			value /= 10;
		}
		reverse(str.begin(), str.end());
		return str;
	}
}

my_string::string ret = my_string::to_string(1234);

	my_string::string ret;
	ret = my_string::to_string(1234);//調(diào)用移動賦值

void PerfectForward(T&& t)
{
	Fun(forward<T>(t));
}

void Func(int&& x)
{
	cout << "rvalue" << endl;
}
void Func(int& x)
{
	cout << "lvalue" << endl;
}
template<class T>
void PerfectForward(T&& t)
{
	Func(t);
}
int main()
{
	PerfectForward(10);//左值
	int a;
	PerfectForward(a);//左值
	PerfectForward(move(a));//左值
}	

	Func(forward<T>(t));

vector<int> v;v.push_back(111);