#include<map> in C++?

Whats this 'map' header file used for?





I tried google to look up on it but ended up giving many complicated coding.


can you please give me a simple C++ programme showing the common usages of map header.








for example, how can it be of use in a hash table storing a name and phone number?





try to give me some code...





thanks

#include%26lt;map%26gt; in C++?
Here's a sample of a hash table type usage:





#include %26lt;iostream%26gt;


#include %26lt;map%26gt;


using namespace std;





int main (int argc, char* argv[]) {





char sample = '+';





/* create a lookup table for operator priorities */


map%26lt;char, unsigned int%26gt; priority;


priority['('] = 0;


priority['['] = 0;


priority['{'] = 0;


priority['*'] = 1;


priority['/'] = 1;


priority['+'] = 2;


priority['-'] = 2;


priority['!'] = 9999;





/* this prints the number 2 */


printf ("priority = %d\n", priority[sample]);


}
Reply:A map is used when you want to use a value as a key to get a definition. Other languages might call it a hash. The map template uses a symmetrical binary tree. The tree uses the less-than operator by default.





To use it as a phone book:





map%26lt;string,string%26gt; phonebook;


string name, number;


..


phonebook[name] = number;


..


map%26lt;string,string%26gt;::iterator iter = phonebook.find( name );


if (iter != phonebook.end())


cout %26lt;%26lt; name %26lt;%26lt; ":" %26lt;%26lt; iter-%26gt;second %26lt;%26lt; endl;


else


cout %26lt;%26lt; name %26lt;%26lt; ": unknown" %26lt;%26lt; endl;
Reply:Map is the STL implementation of hash tables.





Read more about it on wikipedia:


http://en.wikipedia.org/wiki/Map_%28C%2B...





Here's some code:





#include %26lt;iostream%26gt;


#include %26lt;string%26gt;


#include %26lt;map%26gt;





using namespace std;





int main()


{


cout.setf(ios::boolalpha); //make boolean variables output as "true" or "false"


map%26lt;string, bool%26gt; present;


string s;





while (cin %26gt;%26gt; s %26amp;%26amp; s != "end")


present[s] = true;





while (cin %26gt;%26gt; s %26amp;%26amp; s != "end")


cout %26lt;%26lt; s %26lt;%26lt; ' ' %26lt;%26lt; present[s] %26lt;%26lt; endl;


}