目录
1.Vector.h
2.Test.cpp
1.Vector.h
#include <iostream>
#include <cassert>
#include <algorithm>
using namespace std;
template <class T>
class Vector
{
public:typedef T *iterator;typedef const T *const_iterator;iterator begin() const{return _start;}iterator end() const{return _finish;}size_t size() const{return _finish - _start;}size_t capacity() const{return _endofstorage - _start;}T &operator[](size_t i){assert(i < size());return _start[i];}const T &operator[](size_t pos) const{assert(pos < size());return _start[pos];}Vector<T> &operator=(Vector<T> v){swap(v);return *this;}Vector() {}Vector(const Vector<T> &v){reserve(v.capacity());for (auto &e : v){push_back(e);}}Vector(initializer_list<T> il){reserve(il.size());for (auto &e : il){push_back(e);}}template <class InputIterator>Vector(InputIterator first, InputIterator last){while (first != last){push_back(*first);++first;}}// 防止push整型时失效Vector(int n, const T &val = T()){reserve(n);for (int i = 0; i < n; i++){push_back(val);}}Vector(size_t n, const T &val = T()){reserve(n);for (size_t i = 0; i < n; i++){push_back(val);}}~Vector(){if (_start){delete[] _start;_start = _finish = _endofstorage = nullptr;}}void reserve(size_t n){if (n > capacity()){T *temp = new T[n];size_t _size = size();for (size_t i = 0; i < _size; ++i){temp[i] = _start[i];}delete[] _start;_start = temp;_finish = _start + _size;_endofstorage = _start + n;}}void resize(size_t n, T val = T()){if (n > size()){reserve(n);while (_finish != _endofstorage){*_finish = val;_finish++;}}else{// 忽视后面的元素，直接修改_finish的指向_finish = _start + n;}}void push_back(const T &value){if (_finish == _endofstorage){reserve(capacity() == 0 ? 4 : capacity() * 2);}*_finish = value;++_finish;}void pop_back(){assert(!empty());--_finish;}// 检查容器是否为空bool empty(){return _start == _finish;}// 清理容器void clear(){// 让起点与终点重合_start = _finish = _endofstorage = nullptr;}iterator insert(iterator position, const T &val){// 检查插入位置是否在范围之中assert(position <= _finish && position >= _start);// 如果_finish==_endofstorage，那么需要对容器进行扩容if (_finish == _endofstorage){// 储存扩容前的相对位置size_t len = position - _start;reserve(capacity() == 0 ? 4 : capacity() * 2);// 扩容了需要对position进行更新position = _start + len;}iterator it = _finish - 1;while (it >= position){*(it + 1) = *it;it--;}*position = val;_finish++;return position;}iterator erase(iterator position){// 清除的部位必须在范围之内assert(position < _finish && position >= _start);iterator it = position + 1;while (it <= _finish){*(it - 1) = *it;it++;}_finish--;return position;}void swap(Vector<T> &temp){std::swap(_start, temp._start);std::swap(_finish, temp._finish);std::swap(_endofstorage, temp._endofstorage);}private:iterator _start = nullptr;iterator _finish = nullptr;iterator _endofstorage = nullptr;
};template <class T>
void print_Vector(const Vector<T> &v)
{for (size_t i = 0; i < v.size(); i++){cout << v[i] << " ";}cout << endl;
}2.Test.cpp
#include "Vector.h"
void test_Vector1()
{Vector<int> v1;v1.push_back(1);v1.push_back(2);v1.push_back(3);v1.push_back(4);v1.push_back(4);v1.push_back(4);print_Vector(v1);Vector<double> v2;v2.push_back(1.1);v2.push_back(2.2);v2.push_back(3.1);print_Vector(v2);v2.insert(v2.begin(), 11.11);print_Vector(v2);v2.insert(v2.begin(), 11.11);print_Vector(v2);v2.insert(v2.begin(), 11.11);print_Vector(v2);v2.insert(v2.begin(), 11.11);print_Vector(v2);v2.insert(v2.begin(), 11.11);print_Vector(v2);v2.erase(v2.begin());print_Vector(v2);v2.erase(v2.begin() + 4);print_Vector(v2);}void test_Vector2()
{// C++在引入了模板之后对于内置类型也进行了升级，对于int而言，其默认构造函数的初始化结果是0// int i = 1;// int j = int();// int k = int(2);Vector<int> v1;v1.push_back(1);v1.push_back(2);v1.push_back(3);v1.push_back(4);v1.push_back(4);v1.push_back(4);print_Vector(v1);v1.resize(10);print_Vector(v1);v1.resize(3);print_Vector(v1);
}void test_Vector3()
{Vector<int> v1;v1.push_back(1);v1.push_back(2);v1.push_back(3);v1.push_back(4);v1.push_back(4);v1.push_back(4);print_Vector(v1);v1.pop_back();Vector<int> v2(v1);print_Vector(v2);Vector<int> v3;v3.push_back(10);v3.push_back(20);v3.push_back(30);v1 = v3;print_Vector(v1);print_Vector(v3);
}void test_Vector4()
{Vector<int> v1;v1.push_back(1);v1.push_back(2);v1.push_back(3);v1.push_back(4);print_Vector(v1);Vector<int> v2(v1.begin() + 1, v1.end() - 1);print_Vector(v2);string str("abcd");Vector<int> v3(str.begin(), str.end());print_Vector(v3);
}void test_Vector5()
{Vector<int> v1(10, 1);print_Vector(v1);Vector<int> v2(10, 1);print_Vector(v2);Vector<char> v3(10, 'a');print_Vector(v3);
}void test_Vector6()
{auto x = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};cout << typeid(x).name() << endl;cout << sizeof(x) << endl;initializer_list<int> y = {1, 2, 3, 4, 5, 6, 7};// 单参数的构造函数，隐式类型转换string str = "11111"; // 构造 + 拷贝构造 -> 优化 直接构造const string &str1 = "11111"; // 构造临时对象，引用的是临时对象Vector<string> v;v.push_back(str);v.push_back(string("22222"));v.push_back("33333");int i = 1;// 不推荐 -- C++11// int j = { 1 };int k{ 1 };// 跟上面类似// 隐式类型转换+优化// Vector<int> v1 = { 1,2,3,4,5,6,7,8,9,10 };Vector<int> v1{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};for (auto e : v1){cout << e << " ";}cout << endl;// 直接构造Vector<int> v2({10, 20, 30, 40});for (auto e : v2){cout << e << " ";}cout << endl;
}void test_Vector7()
{Vector<string> v;v.push_back("11111");v.push_back("22222");v.push_back("33333");v.push_back("44444");v.push_back("55555");for (auto &e : v){cout << e << " ";}cout << endl;
}void test_Vector8()
{Vector<int> v1;v1.push_back(1);v1.push_back(2);v1.push_back(3);v1.push_back(4);v1.push_back(5);v1.push_back(6);v1.push_back(7);v1.push_back(8);print_Vector(v1);// insert以后，it就失效了，不要使用了Vector<int>::iterator it = v1.begin() + 3;v1.insert(it, 40);print_Vector(v1);it = v1.begin() + 3;cout << *it << endl;
}void test_Vector9()
{// std::Vector<int> v1;Vector<int> v1;v1.push_back(1);v1.push_back(2);v1.push_back(3);v1.push_back(4);v1.push_back(4);v1.push_back(5);// v1.push_back(4);// 删除偶数 -- 迭代器失效以后，不要直接使用，如果要使用按规则重新更新后使用// std::Vector<int>::iterator it = v1.begin();Vector<int>::iterator it = v1.begin();// cout << typeid(it).name() << endl;while (it != v1.end()){if (*it % 2 == 0){it = v1.erase(it);}else{++it;}}for (auto e : v1){cout << e << " ";}cout << endl;
}int main()
{// test_Vector1();// test_Vector2();// test_Vector3();// test_Vector4();// test_Vector5();// test_Vector6();// test_Vector7();// test_Vector8();test_Vector9();return 0;
}
)
