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前言

本文是模拟实现vector部分功能的代码，可以直接拿去使用

一、头文件 .h文件

#include<assert.h>
#include<iostream>
using namespace std;
namespace zz
{
	template<class T>
	class vector
	{
	public:
		typedef T* iterator;
		typedef const T* const_iterator;
		vector()//默认构造
		{}
		vector(const vector<T>& v)//拷贝构造
		{
			reserve(v.size());
			for (auto& e : v)
			{
				push_back(e);
			}
		}
		~vector()//析构
		{
			if (_start)
			{
				delete[] _start;
				_start = _finish = _end_of_storage = nullptr;
			}
		}
		void clear()
		{
			_finish = _start;
		}
		const vector<T> operator=(const vector<T>& v)
		{
			if (this != &v)
			{
				clear();
				reserve(v.size());
				for (auto& e : v)
				{
					push_back(e);
				}
			}
			return *this;
		}
		template <class InputIterator>
		vector(InputIterator first, InputIterator last)
		{
			while (first!=last)
			{
				push_back(*first);
				++first;
			}
		}
		vector(size_t n, const T& val = T())
		{
			reserve(n);
			for (size_t i = 0; i < n; i++)
			{
				push_back(val);

			}
		}
		vector(int n, const T& val = T())
		{
			reserve(n);
			for (size_t i = 0; i < n; i++)
			{
				push_back(val);

			}
		}
		iterator begin()
		{
			return _start;
		}
		iterator end()
		{
			return _finish;
		}
		const_iterator begin() const
		{
			return _start;
		}
		const_iterator end() const
		{
			return _finish;
		}
		bool empty()
		{
			return _start == _finish;
		}
		void reserve(size_t n)
		{
			if (n > capacity())
			{
				size_t old_size = size();
				T* tmp = new T[n];
				//memcpy(tmp, _start, size() * sizeof(T));如果是vector<string>这里就是浅拷贝，要换成下边赋值的写法
				for (size_t i = 0; i < old_size; i++)
				{
					tmp[i] = _start[i];
				}
				delete[] _start;
				_start = tmp;
				_finish = tmp + old_size;
				_end_of_storage = tmp + n;
			}
		}
		T& operator[](size_t i)
		{
			assert(i < size());
			return _start[i];
		}
		size_t size()const
		{
			return _finish - _start;
		}
		size_t capacity()const
		{
			return _end_of_storage - _start;
		}
		void push_back(const T& x)
		{
			if (_finish != _end_of_storage)
			{
				*_finish = x;
				++_finish;
			}
			else
			{
				reserve(capacity() == 0 ? 4 : 2 * capacity());
				*_finish = x;
				++_finish;
			}
		}
		void pop_back()
		{
			assert(!empty());
				--_finish;
		}
		iterator  insert(iterator pos, const T& v)
		{
			assert(pos >= _start);
			assert(pos <= _finish);
			if (_finish == _end_of_storage)
			{
				size_t len = pos - _start;
				reserve(capacity() == 0 ? 4 : 2 * capacity());
				pos = _start + len;
			}
			iterator end = _finish - 1;
			while (end >= pos)
			{
				*(end+1)=*end;
				--end;
			}
			*pos = v;
			++_finish;
			return pos;
		}
		//也会造成迭代器失效
		void earse(iterator pos)
		{
			assert(pos >= _start);
			assert(pos < _finish);
			iterator it = pos + 1;
			while (it!=end())
			{
				*(it - 1) = *it;
				it++;
			}
			--_finish;
		}
		T& operator[](size_t i)const
		{
			assert(i < size());
			return _start[i];
		}
		void resize(size_t n, const T& val = T())
		{
			if (n < size())
			{
				_finish = _start + n;
			}
			else
			{
				reserve(n);
				while (_finish < _start + n)
				{
					*_finish = val;
					++_finish;
				}
			}
		}
	private:
		iterator _start=nullptr;//指向数据块的开始
		iterator _finish=nullptr;//指向有效数据的尾
		iterator _end_of_storage=nullptr;//指向存储容量的尾
	};
	template <class T>
	void print_vector(const vector<T>& v)
	{
		//不加typename的话编译器不能从没有实例化的类模板里边取东西,编译器无法区分const_iterator是类型还是静态成员变量
		typename vector<T>::const_iterator it = v.begin();//这里也可以写成auto it=v.begin();
		while (it != v.end())
		{
			cout << *it << " ";
			++it;
		}
		cout << endl;
		for (auto e : v)
		{
			cout << e << " ";
		}
	}

总结

以上就是vector容器模拟实现的代码，实现了基本的常用的功能，一些很少用的没有实现，纯手打。希望亲们点点发财的小手点个赞！！！！！