vector C++实现

闲来蛋疼，练练手。

参考标准库的vector实现。与STL源码相比大同小异，主要功能都以实现。

#include<iostream>
#include<algorithm>
#include<memory>
using namespace std;
template<class T>
class Vector{
public:
	typedef T value_Type;
	typedef value_Type* Pointer;
	typedef value_Type* iterator;
	typedef value_Type& reference;
	typedef size_t size_type;
	typedef ptrdiff_t difference_type;
protected:
	iterator start;
	iterator finish;
	iterator end_of_storage;
	void insert_aux(iterator position,const T& x);
	void fill_initialize(size_type n, const T& value){
		start = allocate_and_fill(n,value);
		finish = start + n;
		end_of_storage = finish;
	}
	iterator allocate_and_fill(const size_type n, const T& value){
		iterator result = new value_Type[n];
		uninitialized_fill_n(result,n,value);
		return result;
	}
	iterator uninitialized_fill_n(iterator first,size_t n ,const T& x){
		iterator tmp_start = first;
		while(n--){
			*first++ = x;
		}
		return tmp_start;
	}
public:
	iterator begin(){return start;}
	iterator end(){return finish;}
	size_type size(){return size_type(end()-begin());}
	bool empty()const{return begin() == end();}
	reference operator[](size_type n){return *(begin()+n);}
	Vector():start(0),finish(0),end_of_storage(0){}
	Vector(size_type n, const T& value){fill_initialize(n,value);}
	Vector(int n, const T& value){fill_initialize(n,value);}
	Vector(long n, const T& value){fill_initialize(n,value);}
	explicit Vector(size_type n){fill_initialize(n,T());}
	~Vector(){
		destory(start,finish);
		deallocate(start);
	}
	void deallocate(iterator iter){
		delete []iter;
	}
	void destory(iterator iter){
		iter->~T();
	}
	void destory(iterator start, iterator finish){
		int i=0;
		while ((start+i) != finish)
		{
			(start+i)->~T();
			i++;
		}
	}
	reference front(){return *begin();}
	reference back(){return *(end()-1);}
	void push_back(const T& x){
		if(finish!=end_of_storage)
			*finish = x;
		else{
			insert(end(),1,x);
		}
		++finish;
	}
	void pop_back(){
		--finish;
		destory(finish);
	}
	iterator erase(iterator position){
		if(position+1 != end())
			copy(position+1,finish,position);
		--finish;
		destory(finish);
		return position;
	}
	iterator erase(iterator first,iterator last){
		iterator tmp = copy(last,finish,first);
		destory(tmp,finish);
		finish = finish - (last-first);
		return first;
	}
	void resize(size_type new_size,const T& x){
		if(new_size< size())
			erase(begin()+new_size,end());
		else 
			insert(end(),new_size-size(),x);
	}
	void resize(size_type new_size){resize(new_szie,T());}
	void clear(){erase(begin(),end());}
	void insert(iterator position,size_type n,const T& x){
		if(n!=0){
			//备用空间大于新增元素个数
			if(size_type(end_of_storage-finish)>=n){
				T x_copy;
				const size_type elems_after = finish -position;
				iterator old_finish = finish;
				if(elems_after > n){
					uninitialized_copy(finish-n,finish,finish);
					finish += n;
					copy_backward(position,old_finish-n,old_finish);
					fill(position,position+n,x_copy);
				}
				else{
					uninitialized_fill_n(finish,n-elems_after,x_copy);
					finish += n - elems_after;
					uninitialized_copy(position,old_finish,finish);
					finish += elems_after;
					fill(position,old_finish,x_copy);
				}
			}
			else{ //备用空间不足
				const size_type old_size = size();
				const size_type len = old_size + max(old_size,n);
				iterator new_start = reallocate(old_size+2*(max(old_size,n)));//新增元素个数为不足空间个数的2倍
				iterator new_finish = new_start;
				try{
					// 将vector插入点之前的元素复制到新空间
					new_finish = uninitialized_copy(start,position,new_start);
					new_finish = uninitialized_fill_n_my(new_finish,n,x);
					new_finish = uninitialized_copy(position,finish,new_finish);
				}
//#ifdef _STL_USE_EXCEPTIONS
				catch(...){
					//若发生异常，回滚保持原有向量
					destory(new_start,new_finish);
					deallocate(new_start);
					throw;
				}
//#endif
				destory(start,finish);
				deallocate(start);
				start = new_start;
				finish = new_finish;
				end_of_storage = new_start + len;
			}
		}
		
	}
	iterator uninitialized_copy(iterator first,iterator last,iterator res){
		while(first!=last){
			*(res++) = *(first++); 
		}
		return res;
	}
	iterator copy_backward(iterator first,iterator last,iterator res){
		while(last!=first){
			*(--res) = *(--last);
		}
		return res;
	}
	iterator reallocate(const size_t len){
		iterator iter;
		iter = new T[len];
		return iter;
	}
	iterator uninitialized_fill_n_my(iterator start,size_t n, const T& x){
		while(n--){
			*(start++) = x;
		}
		return start;
	}
	iterator find(iterator first,iterator last,const T& value){
		while(first!=last){
			if(*first == value)return first;
			++first;
		}
		return first;
	}
};
void test1(){//测试各种类型数据存储
	Vector<int> Vint(10,2);
	for(Vector<int>::iterator iter =Vint.begin();iter!= Vint.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
	Vector<float>Vflt(10,2.1);
	for(Vector<float>::iterator iter =Vflt.begin();iter!= Vflt.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
	Vector<double>Vdoub(10,2.13);
	for(Vector<double>::iterator iter =Vdoub.begin();iter!= Vdoub.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
	class TT{
		int tmp;
	public:
		TT(int a=0):tmp(a){}
		operator int(){
			return tmp;
		}
	};
	Vector<TT>Vtt(10,TT(3));
	for(Vector<TT>::iterator iter =Vtt.begin();iter!= Vtt.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
}
void test2(){//测试插入
	Vector<int> Vint(10,2);
	Vector<int>::iterator iter =Vint.end();
	Vint.insert(----iter,2,3);
	Vint.push_back(4);
	for(iter=Vint.begin();iter!= Vint.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
}
void test3(){//测试删除
	Vector<int> Vint(10,2);
	Vector<int>::iterator iter =Vint.end();
	Vint.insert(----iter,2,3);
	Vint.push_back(4);
	for(iter=Vint.begin();iter!= Vint.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
	Vector<int>::iterator iter1 = Vint.find(Vint.begin(),Vint.end(),3);
	Vint.erase(iter1,Vint.end());
	for(iter=Vint.begin();iter!= Vint.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
	iter = Vint.end();
	Vint.erase(--iter);
	for(iter=Vint.begin();iter!= Vint.end();++iter)
		cout<<*iter<<" ";
	cout<<endl;
}
int main(){
	cout<<"----------test1---------"<<endl;
	test1();
	cout<<"----------test2---------"<<endl;
	test2();
	cout<<"----------test3---------"<<endl;
	test3();
}