简单实现了构造、析构、push_back、pop_back、operator=、operator[]、clear等函数

template
     
       class my_vector {private:	int count;	int alloc_size;	T *arr;public:	my_vector():count(0),alloc_size(0),arr(NULL)	{	}	my_vector(int n, T ele): count(0),alloc_size(n)	{		arr = new T[n];		while(n--)		{			push_back(ele);		}	}	my_vector(const my_vector &other):count(0),alloc_size(0),arr(NULL)	{		*this = other;	}	my_vector
      
       & operator=(const my_vector &other)	{		count = other.size();		alloc_size = count;		T *oldarr = arr;		arr = new T[count];		for(int i = 0; i < count; i++)			arr[i] = other[i];		delete []oldarr;	}	void push_back(T ele)	{		if(count == alloc_size)		{			T *oldarr = arr;			int new_size;			if(alloc_size == 0)				new_size = 1;			else				new_size = alloc_size*2;			arr = new T[new_size];			for(int i = 0; i < count; i++)			{				arr[i] = oldarr[i];			}			alloc_size = new_size;			delete []oldarr;		}		arr[count] = ele;		count++;	}	void pop_back()	{		if(count > 0)			count--;	}	int size()	{		return count;	}	T& operator[](int pos)	{		assert(pos < count);		return arr[pos];	}	void clear()	{		count = 0;	}	~my_vector()	{		count = 0;		alloc_size = 0;		delete []arr;		arr = NULL;	}};