模板 模板容器的实现

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/weixin_39087263/article/details/83758816

template<typename T>
class Vector
{
public:
	Vector(int _size = 10):num(0),resize(_size)
	{
		ptr = new T[resize];
	}
	~Vector()
	{
		delete [] ptr;
		ptr = NULL;
	}
	Vector(const Vector&src)
	{
		num = src.num;
		resize = src.resize;
		ptr = new T[src.resize];
		for(int i =0;i<src.num;i++)
		{
			ptr[i] =src[i];
		}
	}
   Vector<T>& operator=(const Vector<T> &src) 
	{
		if(ptr = src.ptr)
		{
			return *this;
		}
		delete []ptr;
		num = src.num;
		resize = src.resize;
		ptr = new T[src.resize];
		for(int i =0;i<src.num;i++)
		{
			ptr[i] =src[i];
		}
	}
   void Push_back(const T&val)
	{
		if(num == resize)
		{
			_resize();
		}
		ptr[num++] = val; 
	}
	void Pop_back()
	{
		if(num==0)
		{
			return ;
		}
		ptr--;
	}
	int operator[](int i)
	{
		return ptr[i];
	}

private:
	int num;//当前元素大小
	int resize;//扩容大小
	T *ptr;//指向当前元素
	void _resize()
	{
		T*tmp = new T[resize*2];
		resize*=2;
		for(int i=0;i<num;i++)
		{
			tmp[i] = ptr[i];
		}
		delete []ptr;
		ptr = tmp;
	}
};

int main()
{
	Vector<int>arr;
for(int i = 0;i<5;i++)
{
	arr.Push_back(i);
	cout<<arr[i]<<endl;
}
  arr.Pop_back();
  for(int i = 0;i<4;i++)
{
	cout<<arr[i]<<endl;
}
system("pause");
return 0;
}