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1、vector的模拟实现.h

#pragma oncenamespace My_vector
{template<class T>class vector{public:typedef T* iterator; //typedef受访问限定符限制，要放成公有typedef const T* const_iterator;iterator begin(){return _start;}iterator end(){return _finish; //end和_finish都指向最后一个数的下一个}const_iterator begin() const{return _start;}const_iterator end() const{return _finish;}size_t capacity() const{return _endofstorage - _start;}size_t size() const{return _finish - _start;}//无参构造vector():_start(nullptr), _finish(nullptr), _endofstorage(nullptr){}//n个val值构造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 (int i = 0; i < n; i++){push_back(val);}}//拷贝构造vector(const vector<T>& v):_start(nullptr),_finish(nullptr),_endofstorage(nullptr){reserve(v.capacity());for (auto& e : v){push_back(e);}}//v3 = v1void swap(vector<int>& v){std::swap(_start, v._start);std::swap(_finish, v._finish);std::swap(_endofstorage, v._endofstorage);}vector<T>& operator=(vector<T> tmp) //传参用了拷贝构造{swap(tmp);return *this;}//迭代区间构造//类模板里可以套函数模板template<class InputIterator>vector(InputIterator first, InputIterator last):_start(nullptr), _finish(nullptr), _endofstorage(nullptr){while (first != last){push_back(*first);++first;}}~vector(){delete[] _start;_start = _finish = _endofstorage = nullptr;}void reserve(size_t n){size_t sz = size();if (n > capacity()){T* tmp = new T[n];if (_start){//memcpy(tmp, _start, sizeof(T) * sz);for (size_t i = 0; i < sz; i++){tmp[i] = _start[i];}delete[] _start;}_start = tmp;_finish = _start + sz;_endofstorage = _start + n;}}//void rsize(size_t n, T val = T())void rsize(size_t n, const T& val = T()) //匿名对象具有常性，要加const{if (n > size()){reserve(n);while (_finish < _start + n){*_finish = val;++_finish;}}if (n <= size()){_finish = _start + n;}}void push_back(const T& x){if (_finish == _endofstorage){/*size_t sz = size();size_t cp = capacity() == 0 ? 4 : capacity() * 2;T* tmp = new T[cp];if (_start){memcpy(tmp, _start, sizeof(T) * sz);delete[] _start;}_start = tmp;_finish = _start + sz;_endofstorage = _start + cp;*/reserve(capacity() == 0 ? 4 : capacity() * 2);}*_finish = x;++_finish;}//insert、erase操作后迭代器都会失效，不能再访问void insert(iterator pos, const T& x){assert(pos >= _start);assert(pos <= _finish);if (_finish == _endofstorage){size_t len = pos - _start;reserve(capacity() == 0 ? 4 : capacity() * 2);pos = _start + len; //扩容后要更新pos的相对位置}iterator end = _finish - 1;while (end >= pos){*(end + 1) = *end;--end;}*pos = x;++_finish;}iterator erase(iterator pos){assert(pos >= _start);assert(pos < _finish);iterator it = pos + 1;while (it < _finish){*(it - 1) = *it;it++;}--_finish;return pos;}T& operator[](size_t pos){assert(pos < size());return _start[pos];}const T& operator[](size_t pos) const{assert(pos < size());return _start[pos];}private:iterator _start;iterator _finish;iterator _endofstorage;};void Test1(){vector<int> v;v.push_back(1);v.push_back(2);v.push_back(3);v.push_back(4);v.push_back(5);v.push_back(6);for (size_t i = 0; i < v.size(); i++){cout << v[i] << " ";}cout << endl;vector<int>::iterator it = v.begin();while (it != v.end()){*it *= 10;cout << *it << ' ';it++;}cout << endl;for (auto e : v){cout << e << " ";}cout << endl;}void Test2(){vector<int*> v1;v1.rsize(5);vector<string> v2;//v2.rsize(5, string("xxx")); //匿名对象v2.rsize(5, "xxx"); //隐式类型转换for (auto e : v1){cout << e << ' ';}cout << endl;for (auto e : v2){cout << e << ' ';}cout << endl;}void Test3(){vector<int> v;v.push_back(1);v.push_back(2);v.push_back(3);v.push_back(4);v.push_back(5);v.push_back(6);for (auto e : v){cout << e << ' ';}cout << endl;v.insert(v.begin() + 2, 30);v.insert(v.begin(), 0);for (auto e : v){cout << e << ' ';}cout << endl;v.erase(v.begin());v.erase(v.begin() + 2);for (auto e : v){cout << e << ' ';}cout << endl;}void Test4(){vector<int> v;v.push_back(1);v.push_back(2);v.push_back(3);v.push_back(4);v.push_back(5);v.push_back(6);v.push_back(6);v.push_back(7);v.push_back(8);auto it = v.begin();while (it != v.end()){if (*it % 2 == 0){it = v.erase(it);//it = it - 1;}else{it++; //不删除再++}}for (auto e : v){cout << e << ' ';}cout << endl;}void Test5(){vector<string> v;v.push_back("111111111111111111111");v.push_back("111111111111111111111");v.push_back("111111111111111111111");v.push_back("111111111111111111111");v.push_back("111111111111111111111");for (auto e : v){cout << e << " ";}cout << endl;}void Test6(){vector<int> v;v.push_back(1);v.push_back(2);v.push_back(3);v.push_back(4);v.push_back(5);for (auto e : v){cout << e << " ";}cout << endl;vector<int> v2(v);for (auto e : v2){cout << e << " ";}cout << endl;vector<int> v3;v3.push_back(3);v3.push_back(4);v3.push_back(5);v3.push_back(6);v3.push_back(7);v2 = v3;for (auto e : v2){cout << e << " ";}cout << endl;}void Test7(){vector<int> v1(10, 15);vector<int> v2(v1.begin(), v1.end());for (auto e : v2){cout << e << " ";}cout << endl;vector<string> v3(5, "xxx");vector<string> v4(v3.begin(), v3.end());for (auto e : v4){cout << e << " ";}cout << endl;}
}

2、Test.cpp

#define _CRT_SECURE_NO_WARNINGS 1
#include <iostream>
#include <assert.h>
#include <string.h>
#include <vector>
using namespace std;#include "1、vector的模拟实现.h"int main()
{My_vector::Test7();return 0;
}