【C++进阶(二)】STL大法--vector的深度剖析以及模拟实现

vector<int> v1;
vector<int> v2(10,1);
vector<int> v3(v2);

string str("abcdefg");
vector<string> vv(str.begin(),str.end());

vector<int> vv{1,2,3,4,5,6};
vector<int>::iterator it = vv.begin();
while(it!=vv.end())
{
  cout<<*it;
  it++;
}

vector<int> vv{1,2,3,4,5,6,7,8,9};
auto pos = find(vv.begin(),vv.end(),5);
cout<<*pos;

vector<int> vv{5,7,3,9,6,4,1,2,8};
sort(vv.begin().vv.end());

vector<int> vv{1,2,3,4,5,6,7,8,9};
auto pos = find(vv.begin(),vv.end(),5);
vv.insert(pos,100);

vector<int> vv{1,2,3,4,5,6,7,8,9,100};
auto pos = find(vv.begin(),vv.end(),100);
vv.erase(pos);
//删除一个区间
vv.erase(vv.begin()+2,vv.end()-2);

vector<int> vv{1,2,3,4,5,6,7,8,9};
for(int i=0;i<vv.size();i++)
{
  cout<<vv[i]<<" ";
}

template<class T>
class vector
{
public:
  typedef T* iterator;
private:
  iterator _start;
  iterator _finish;
  iterator _endof_storage;

size_t size() const
{
  return _finish - _start;
}
size_t capacity() const
{
  return _endof_storage - _finish;
}
bool empty() const
{
  return (size()==0);
}

void reserve(size_t n)
{
  if (n > capacity())
  {
    size_t sz = size();
    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;
    _end_of_storage = _start + n;
  }
}

void resize(size_t n, const T& val = T())
{
  if (n > capacity())
  {
    reserve(n);
  }
  if (n > size())
  {
    // 初始化填值
    while (_finish < _start + n)
    {
      *_finish = val;
      ++_finish;
    }
  }
  else
  {
    _finish = _start + n;
  }
}

int tmp1 = int();
int tmp2 = int(10);

vector()
  :_start(nullptr)
  , _finish(nullptr)
  , _end_of_storage(nullptr)
{}

vector(size_t n, const T& val = T())
  :_start(nullptr)
  , _finish(nullptr)
  , _end_of_storage(nullptr)
{
  reserve(n);//开辟n个空间
  for (size_t i = 0; i < n; ++i)
  {
    push_back(val);//给初始值赋值
  }
}

string str("abcdefg");
vector<string> vv(str.begin(),str.end());

template <class InputIterator>
vector(InputIterator first, InputIterator last)
  :_start(nullptr)
  , _finish(nullptr)
  , _end_of_storage(nullptr)
{
  while (first != last)
  {
    push_back(*first);
    ++first;
  }
}

~vector()
{
  delete[] _start;
  _start = _finish = _end_of_storage = nullptr;
}

vector(const vector<T>& v)
  :_start(nullptr)
  , _finish(nullptr)
  , _endof_storage(nullptr)
  {
    reserve(v.size());
    for (const auto& e : v)
    {
      push_back(e);
    }
  }