std::vector的核心框架接口的模拟实现bit::vector
#pragma once
#include<iostream>
#include<assert.h>
#include<string>
#include<algorithm>
#include<vector>
using std::cout;
using std::endl;
namespace bit
{
template<class T>
class vector
{
public:
typedef T* iterator;
typedef const T* const_iterator;
iterator begin()
{
return _start;
}
iterator end()
{
return _finish;
}
const_iterator begin()const
{
return _start;
}
const_iterator end()const
{
return _finish;
}
vector()
{}
vector(const vector<T>& v)
{
reserve(v.capacity());
for (auto& e : v)
{
push_back(e);
}
}
vector(std::initializer_list<T> il)
{
size_t n = il.size();
reserve(n * sizeof(T));
for (auto e : il)
{
push_back(e);
}
}
template<class InputIterator>
vector(InputIterator first, InputIterator last)
{
while (first < last)
{
push_back(*first);
++first;
}
}
vector(size_t n, const T& val = T())
{
resize(n, val);
}
vector(int n, const T& val = T())
{
resize(n, val);
}
void swap(vector<T> v)
{
std::swap(_start, v._start);
std::swap(_finish, v._finish);
std::swap(_endofstorage, v._endofstorage);
}
vector<T>& operator=(vector<T> v)
{
swap(v);
}
~vector()
{
delete[] _start;
_start= _finish = _endofstorage = nullptr;
}
size_t size()const
{
return _finish - _start;
}
T& operator[](size_t pos)
{
assert(pos < size());
return _start[pos];
}
const T& operator[](size_t pos)const
{
assert(pos < size());
return _start[pos];
}
size_t capacity()const
{
return _endofstorage - _start;
}
void reserve(size_t n)
{
if (n > capacity())
{
T* tmp = new T[n];
size_t old_size = size();
for (size_t i = 0; i < old_size; i++)
{
tmp[i] = _start[i];
}
delete[] _start;
_start = tmp;
_finish = tmp + old_size;
_endofstorage = tmp + n;
}
}
void resize(size_t n, const T& val = T())
{
if (n > size())
{
reserve(n);
while (_finish < _start + n)
{
*_finish = val;
++_finish;
}
}
else
{
_finish = _start + n;
}
}
void push_back(const T& val)
{
insert(_finish, val);
}
void pop_back()
{
erase(--end());
}
bool empty()
{
return _start==_finish;
}
void insert(iterator pos, const T& val)
{
assert(pos >= _start);
assert(pos <= _finish);
if (size() == capacity())
{
size_t len = pos - _start;
reserve(capacity() == 0 ? 4 : 2 * capacity());
pos = _start + len;
}
iterator it = _finish -1;
while (it >= pos)
{
*(it + 1) = *it;
--it;
}
*pos = val;
++_finish;
}
iterator erase(iterator pos)
{
assert(pos >= _start);
assert(pos < _finish);
iterator it = pos + 1;
while (it < _finish - 1)
{
*it = *(it + 1);
it++;
}
--_finish;
return pos;
}
private:
iterator _start=nullptr;
iterator _finish=nullptr;
iterator _endofstorage=nullptr;
};
template <class T>
void print_vector(const vector<T>& v)
{
for (int i = 0; i < v.size(); i++)
{
cout << v[i] << " ";
}
cout << endl;
}
}