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C++容器之vector模拟实现（代码纯享版！！！）

news 2025/5/16 9:31:05

前言

一、头文件 .h文件

总结

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 << " ";}}