1 #ifndef ALLOCATOR_H 2 #define ALLOCATOR_H  3  4 #include <stddef.h> 5 #include <limits> 6  7 template <typename T> 8 class Allocator 9 {10 public:11     typedef size_t      size_type;12     typedef ptrdiff_t   difference_type;13     typedef T*          pointer;14     typedef const T*    const_pointer;15     typedef T&          reference;16     typedef const T&    const_reference;17     typedef T           value_type;18 19     template <typename V>20     struct rebind21     {22         typedef Allocator<V> other;23     };24 25     pointer address(reference value) const { return &value; }26     const_pointer address(const_reference value) const { return &value; }27 28     Allocator() throw() { }29     Allocator(const Allocator &v) throw() { }30     template <typename V>31     Allocator(const Allocator<V> &v) { } 32 33     ~Allocator() throw() { }34 35     size_type max_size() const throw()36     { return std::numeric_limits<size_type>::max() / sizeof(T); }37 38     pointer allocate(size_type num)39     { return (pointer)(::operator new(num * sizeof(T))); }40 41     void construct(pointer p, const T &value)42     { new((void*)p) T(value); }43 44     void destroy(pointer p)45     { p->~T(); }46 47 48     void deallocate(pointer p, size_type num)49     { ::operator delete((void*)p); }50 51 };52 53 54 template <typename T, typename V>55 bool operator==(const Allocator<T> &a, const Allocator<V> &b)56 { return true; }57 58 59 template <typename T, typename V>60 bool operator!=(const Allocator<T> &a, const Allocator<V> &b)61 { return false; }
62 #endif  /*ALLOCATOR_H*/

 1 #include "alloc.hpp" 2 #include <string> 3 #include <vector> 4 using namespace std; 5  6  7 int main(int argc, char const *argv[]) 8 { 9     vector<string, Allocator<string> > vec(10, "haha");10 11     vec.push_back("foo");12     vec.push_back("bar");13 14     //Allocator<Test>::rebind<Test2>::other alloc;15 16     return 0;17 }