C++ Tutorial/map multimap/multimap

A multimap can store duplicates

<source lang="cpp">#include <map>

1. include <iostream>

using namespace std; typedef map <int, string> MAP_INT_STRING; typedef multimap <int, string> MMAP_INT_STRING; int main () {

   MMAP_INT_STRING mmapIntToString;
   mmapIntToString.insert (pair <int, string> (1000, "One Thousand"));
   mmapIntToString.insert (MMAP_INT_STRING::value_type (1000, "Thousand"));
   cout << endl << "The multimap contains " << mmapIntToString.size ();
   cout << " key-value pairs." << endl;
   cout << "The elements in the multimap are: " << endl;

   return 0;

}</source>

Instantiating an STL map and multimap (Key Type: integer, Value Type: string)

<source lang="cpp">#include <map>

1. include <string>

int main () {

   using namespace std;
   map <int, string> mapIntegersToString;
   multimap <int, string> mmapIntegersToString;
   return 0;

}</source>

make a dictionary out of a multimap

<source lang="cpp">#include <algorithm>

1. include <iostream>
2. include <map>
3. include <utility>

using namespace std; int main( ) {

  const char* word[] = { "A", "B", "C", "D","E" };
  const char* clue[] = { "a", "b","c", "d","e" };
  map<string,string> dictionary1;
  transform( word, word+sizeof(word)/sizeof(word[0]), clue,inserter( dictionary1, dictionary1.end() ),make_pair<string,string> );
  typedef multimap<string,string> Dictionary;
  Dictionary dictionary2( dictionary1.begin(),dictionary1.end() );
  dictionary2.insert( make_pair( "POPS", "Bursts" ) );
  dictionary2.insert( make_pair( "POPS", "Fathers" ) );
  dictionary2.insert( make_pair( "ADAM", "Madam" ) );
  pair<Dictionary::iterator,Dictionary::iterator> range = dictionary2.equal_range( "POPS" );
  for( Dictionary::iterator i = range.first; i != range.second; ++i )
     cout << "\nPOPS - " << i->second;
  for( Dictionary::iterator i = dictionary2.begin();
     i != dictionary2.end(); ++i )
     cout << i->first << " - " << i->second << endl;

}</source>

multimap can return the number of pairs with the same key

<source lang="cpp">#include <map>

1. include <iostream>

using namespace std; typedef map <int, string> MAP_INT_STRING; typedef multimap <int, string> MMAP_INT_STRING; int main () {

   MMAP_INT_STRING mmapIntToString;
   mmapIntToString.insert (MMAP_INT_STRING::value_type (3, "Three"));
   mmapIntToString.insert (MMAP_INT_STRING::value_type (45, "Forty Five"));
   cout << "The number of pairs in the multimap with 1000 as their key: "
       << mmapIntToString.count (1000) << endl;
   return 0;

}</source>