C++入门-程序员修炼手册-模拟实现vector类

#define _CRT_SECURE_NO_WARNINGS
#include
#include
#include
#include
using namespace std;

namespace Etta
{
	template
	class vector
	{
	public:
		typedef T* iterator;
		typedef const T* const_iterator;
		vector()//无参构造函数
			:_start(nullptr)
			,_finish(nullptr)
			,_end_of_storage(nullptr)
		{}
		//vector(size_t n, T val);
		template
		vector(InputIterator first, InputIterator last)//带参构造
			: _start(nullptr)
			, _finish(nullptr)
			, _end_of_storage(nullptr)
		{
			while (first != last)
			{
				push_back(*first);
				first++;
			}
		}
		//v1(v2)
		vector(const vector& v)
			:_start(nullptr)
			, _finish(nullptr)
			, _end_of_storage(nullptr)
		{
			_start = new T[v.capacity()];
			for (size_t i = 0; i < v.size(); i++)
			{
				_start[i] = v._start[i];//深拷贝，避免对同一块空间多次析构
			}
			_finish =_start+ v.size();
			_end_of_storage =_start+v.capacity();

		}
		void swap(vector& v)
		{
			::swap(_start,v._start);
			::swap(_finish,v._finish);
			::swap(_end_of_storage,v._end_of_storage);
		}
		vector &operator=(vector v)
		{
			swap(v);
			return *this;
		}
		~vector()//析构函数
		{
			if (_start)
			{
				delete[] _start;
			}
			_start = _finish = _end_of_storage = nullptr;
		}
		size_t size() const 
		{
			return _finish-_start;
		}
		size_t capacity() const   
		{
			return _end_of_storage - _start;
		}
		iterator begin()//可读可写
		{
			return _start;
		}
		iterator end()
		{
			return _finish;
		}
		const_iterator begin() const 
		{
			return _start;
		}
		const_iterator end() const
		{
			return _finish;;
		}
		bool empty()const
		{
			return _start==_finish;
		}
		void push_back(const T& x)
		{
			if (_finish == _end_of_storage)
			{
				size_t newcapacity = capacity() == 0 ? 4 : capacity() * 2;
				reserve(newcapacity);
			}
			*_finish = x;
			++_finish;
		}
		void reserve(size_t n)//小于capacity不处理，大于处理
		{
			if (n > capacity())
			{
				size_t sz = size();
				T*tmp = new T[n];
				//memcpy(_start.tmp, szieof(T)*sz);//不用这个的原因是对string类无法实现深拷贝
				for (size_t i = 0; i < sz; i++)
				{
					tmp[i] = _start[i];
				}
				delete[] _start;
				_start = tmp;
				_finish = _start + sz;
				_end_of_storage = _start + n;
			}

		}
		void resize(size_t n, T val = T())//隐式类型转换，给默认的缺省值
		{
			if (n < size())
			{
				_finish = _start + n;
			}
			else
			{
				if (n>capacity())
				{
					reserve(n);
				}
				while (_finish < _start + n)
				{
					*_finish = val;
					_finish++;
				}
			}
		}
		void insert(iterator pos, const T &x)
		{
			if (_finish == _end_of_storage)
			{
				size_t len = pos - _start;
				size_t newcapacity = capacity() == 0 ? 4 : capacity() * 2;
				reserve(newcapacity);
				//扩容以后更新pos位置，防止pos失效
				pos = _start + len;
			}
			iterator end = _finish-1;
			while (end >= pos)
			{
				*(end + 1) = *end;
				end--;
			}
			*pos = x;
			++_finish;
		}
		iterator erase(iterator pos)
		{
			assert(capacity());
			iterator it = pos + 1;
			if (it != _finish)
			{
				*(it - 1) = *it;
				it++;
			}
			_finish--;
			return pos;
		}
		void pop_back()
		{
			assert(!empty());
			--_finish;
		}
	private:
		iterator _start;
		iterator _finish;
		iterator _end_of_storage;
	};
	template
	void PrintVector( const Con& v)
	{
		Con::const_iterator it = v.begin();
		while (it != v.end())
		{
			cout << *it << " ";
			++it;
		}
		cout << endl;
	}
	void test_vector()
	{
		vector v;
		v.push_back(1);
		v.push_back(2);
		v.push_back(3);
		v.push_back(4);
		PrintVector(v);
		v.reserve(10);
		v.push_back(1);
		v.push_back(1);
		PrintVector(v);
		vectorv2(v);
		PrintVector(v2);
	}
	void test_vector1()
	{
		vector v;
		v.push_back(1);
		v.push_back(2);
		v.push_back(3);
		v.push_back(4);
		v.resize(10, 2);
		PrintVector(v);
		v.erase(v.begin());
		PrintVector(v);
	}
	void test_vector2()
	{
		vectorv;
		v.push_back("11111");
		v.push_back("222");
		vectorv1;
		v1.push_back("adasada");
		v1.push_back("dsfsdf");
		v.swap(v1);
		PrintVector(v);
	}
}
int main()
{
	//Etta::test_vector1();
	/*vector v1;
	v1.erase(v1.begin());*/
	Etta::test_vector2();


	return 0;
}