#ifndef ALLOCATOR_HPP
#define ALLOCATOR_HPP#include <stddef.h>
#include <limits>template <typename T>
class Allocator
{
public:typedef size_t size_type;typedef ptrdiff_t difference_type;typedef T*  pointer;typedef const T* const_pointer;typedef T& reference;typedef const T& const_reference;typedef T value_type;//Allocator::rebind<T2>::othertemplate <typename V>struct rebind{typedef Allocator<V> other;};pointer address(reference value) const { return &value; }const_pointer address(const_reference value) const { return &value; }Allocator() throw() {   }Allocator(const Allocator &) throw() {  }//不同类型的allcator可以相互复制template <typename V> Allocator(const Allocator<V> &other) { } ~Allocator() throw() {  }//最多可以分配的数目size_type max_size() const throw(){ return std::numeric_limits<size_type>::max() / sizeof(T); }//分配内存，返回该类型的指针
    pointer allocate(size_type num){ return (pointer)(::operator new(num * sizeof(T))); }//执行构造函数，构建一个对象void construct(pointer p, const T &value){ new ((void*)p) T(value); }//销毁对象void destroy(pointer p){ p->~T(); }//释放内存void deallocate(pointer p, size_type num){ ::operator delete((void *)p); }
};//这两个运算符不需要friend声明
template <typename T, typename V>
bool operator==(const Allocator<T> &, const Allocator<V> &) throw()
{ return true; }template <typename T, typename V>
bool operator!=(const Allocator<T> &, const Allocator<V> &) throw()
{ return false; }#endif

Allocator<Test>::rebind<Test2>::other alloc;

#include "Allocator.hpp"
#include <string>
#include <vector>
using namespace std;int main(int argc, char const *argv[])
{vector<string, Allocator<string> > vec(10, "haha");vec.push_back("foo");vec.push_back("bar");//Allocator<Test>::rebind<Test2>::other alloc;return 0;
}