Should I implement this using string hash or multimap..

From:
"Jonay Aloat" <jonhat@comcast.net>
Newsgroups:
comp.lang.c++.moderated
Date:
15 Sep 2006 09:53:21 -0400
Message-ID:
<iaCdnYP6rpSm1ZfYnZ2dnUVZ_sOdnZ2d@comcast.com>
I need to implement the following. Shoul I use multimap or write a string
hash class? ie

Brand Product
==========================
Samson Television
Samsung Television
Samsung VCR
Samsung DVD Player
Samsunk Television

The brand is the key and the product is the data.

If I use multimap, then I can implement it using something like this

typedef std::multimap<string, string> mmap;
typedef std::multimap<string, string>::iterator mapIter;

mmap product_map;
product_map.insert( pair<string, string> string a(Samsung), string
b(Television));
...
...
...
To find the product in brand, all I have to do is iterate using lower and
upper bound.

mapIter lowerB = product_map.lower_bound("Samsung");
mapIter upperB = product_map.upper_bound("Samsung");

for (lowerB; lowerB != upperB; ++lowerB) {
    string p = (*lowerB).second;
    if ( strcmp (p.c_str(), "VCR") == 0 ) ) {
            //do something
    } else {
            //do something
    }
}

Assume that I have a lot of data. Is this implementation efficient? I know
using string as the key is not a good idea. Is there a better way to do
this? Is the performance better using hash? How do I implent the hash
function.

Thanks in advance..

-Jonny

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