C哈希表与C++ HASHYMAP映射

我比较下面的C++代码和C语言和C语言(MUNO 2.4)似乎更快。C++代码有什么问题吗?

 #include <map>
 #include <string>
 #include <iostream>
 #include <ext/hash_map>
 #include <boost/any.hpp>

 int main()
 {
    //std::map<long, long> m;
    // hash_map is a little bit faster
    __gnu_cxx::hash_map<long, long> m;

    for( long i = 0; i < 1000000; ++i )
    {
        m[i]  = i;
    }

 }

和C

 using System;
 using System.Collections;

 public int Main()
 {
     Hashtable m = new Hashtable();

     for( long i = 0; i < 1000000; ++i )
     {
        m[i]  = i;
     }

}

在同一台机器上,C代码的速度实际上是它的两倍。

$ time ./a.out

real    0m1.028s
user    0m0.986s
sys     0m0.041s

$ time mono test.exe

real    0m0.603s
user    0m0.732s
sys     0m0.090s