hash_map

From:
"tat" <tuantran167@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
28 Sep 2006 20:38:37 -0400
Message-ID:
<1159477554.466388.238570@i3g2000cwc.googlegroups.com>
Hi,

My question is kind of off-topic. I am trying to learn hash_map. I have
the below. I expect that I get the following output
---
The key is in there
362:369 10.329
-----

I instead got
--------
362:369 0
---------

Can someone explain me why? What's wrong with my code? I compiled and
ran this code on Debian GNU/Etch with g++ version 4.0.4.

Thanks,
tat

#include <cstdlib>
#include <iostream>
#include <string>
#include <ext/hash_map>

int main(int argc, char* argv[])
{
   __gnu_cxx::hash_map<const char*, float,
   __gnu_cxx::hash<const char*> > sourceMatrix;

   const std::string& p1 = "362:369";
   const std::string& p2 = "369:362";
   const std::string& p3 = "335:376";
   const std::string& p4 = "376:335";
   const std::string& p5 = "427:450";
   const std::string& p6 = "450:427";

   sourceMatrix[p1.c_str()] = sourceMatrix[p2.c_str()] = 10.329;
   sourceMatrix[p3.c_str()] = sourceMatrix[p4.c_str()] = 19.142;
   sourceMatrix[p5.c_str()] = sourceMatrix[p6.c_str()] = 20.383;

   const std::string& key = "362:369";

   if (sourceMatrix.find(key.c_str()) != sourceMatrix.end()) {
     std::cout << " The key is in there\n";
   }

   std::cout << key << "\t" << sourceMatrix["362:369"]<< "\n";
   return EXIT_SUCCESS;
}

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