STL empty container sizes

// Visual Studio 2010 standard library empty container sizes
/*
win32, release
vector size:16
map size:16
string size:28
hashtable size:44
unordered_set size:44
set size:16

win32, debug
vector size:20
map size:20
string size:32
hashtable size:56
unordered_set size:56
set size:20

*/

#include "stdafx.h"
#include <vector>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <set>
#include <iostream>



int _tmain(int argc, _TCHAR* argv[])
{
    std::cout << "vector size:"<<sizeof(std::vector<int>) << std::endl;
    std::cout << "map size:"<<sizeof(std::map<int,int>) << std::endl;
    std::cout << "string size:"<<sizeof(std::string) << std::endl;
    std::cout << "hashtable size:"<<sizeof(std::unordered_map<int,std::string>) << std::endl;
    std::cout << "unordered_set size:"<<sizeof(std::unordered_set<int>) << std::endl;
    std::cout << "set size:"<<sizeof(std::set<int>) << std::endl;
    return 0;
}