GNU hash_set vs std::set

testset.cpp

#include <string>
#include <iostream>
#include <cstdlib>
#include <ctime>
#include <sstream>
#if defined(__GNUC__) && defined(WITH_HASHSET)
#include <ext/hash_set>
namespace __gnu_cxx
{
     /* hack from http://www.moosechips.com/2008/10/using-gcc-c-hash-classes-wit
h-strings/ */
template<> struct hash< std::string >
        {
                size_t operator()( const std::string& x ) const
                {
                        return hash< const char* >()( x.c_str() );
                }
        };
}

typedef __gnu_cxx::hash_set<std::string, __gnu_cxx::hash<std::string> > set_of_string;
#else
#include <set>
typedef std::set<std::string> set_of_string;
#endif

using namespace std;

int main(int argc,char** argv)
	{
	set_of_string rs_list;
	for(int t=0;t<2;++t)
		{
		srand(0U);

		for(int i=0;i< 10000000;++i)
			{
			ostringstream os;
			os << "rs" << rand();
			string rs(os.str());
			if(t==0)
				{
				rs_list.insert(rs);
				}
			else
				{
				set_of_string::iterator r=rs_list.find(rs);
				if(r!=rs_list.end()) rs_list.erase(r);
				}
			}
		}
		
	cout << "Time: "<< (((float)std::clock())/CLOCKS_PER_SEC) << "seconds.\n";
	return 0;
	}