C++ Tutorial/map multimap/multimap insert

Insert into multimap with key-value pair

<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 << endl << "The multimap contains " << mmapIntToString.size ();
   cout << " key-value pairs." << endl;
   cout << "The elements in the multimap are: " << endl;

   return 0;

}</source>

Insert into multimap with make-pair function

<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 (make_pair (-1, "Minus One"));
   cout << endl << "The multimap contains " << mmapIntToString.size ();
   cout << " key-value pairs." << endl;
   cout << "The elements in the multimap are: " << endl;

   return 0;

}</source>

Insert value pair to int, double multimap

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <map>

int main() {

  std::multimap< int, double, std::less< int > > pairs; // declare the multimap pairs
  cout << "There are currently " << pairs.count( 15 )
     << " pairs with key 15 in the multimap\n";
  // insert two value_type objects in pairs
  pairs.insert( std::multimap< int, double, std::less< int > >::value_type( 15, 2.7 ) );
  pairs.insert( std::multimap< int, double, std::less< int > >::value_type( 15, 99.3 ) );
  cout << "After inserts, there are " << pairs.count( 15 )
     << " pairs with key 15\n\n";
  cout << endl;
  return 0;

}</source>

There are currently 0 pairs with key 15 in the multimap
After inserts, there are 2 pairs with key 15

uses a multimap to store names and phone numbers.

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

1. include <map>
2. include <string>

using namespace std; void shownumbers(const char *n, multimap<string, string> mp); int main() {

 multimap<string, string> phonemap;
 // Insert elements by using operator[].
 phonemap.insert(pair<string, string>("A", "B: 555-1111"));
 phonemap.insert(pair<string, string>("C", "D: 555-1234"));
 phonemap.insert(pair<string, string>("E", "F: 555-1122"));
 phonemap.insert(pair<string, string>("J", "K: 314 555-2222"));
 phonemap.insert(pair<string, string>("L", "M: 314 555-3322"));
 phonemap.insert(pair<string, string>("O", "P: 666 555-9876"));
 phonemap.insert(pair<string, string>("Q", "R: 555 555-1010"));
 phonemap.insert(pair<string, string>("S", "T: 444 555-9999"));
 shownumbers("A", phonemap);
 shownumbers("C", phonemap);
 shownumbers("E", phonemap);
 int count = phonemap.erase("A");
 cout << count << " elements have been removed.\n\n";
 shownumbers("Ken", phonemap);
 return 0;

} // Show all numbers for a given name. void shownumbers(const char *n, multimap<string, string> mmp) {

 multimap<string, string>::iterator itr;
 // Find the first matching key.
 itr = mmp.find(n);
 if(itr != mmp.end()) {
   cout << "the numbers for " << n << ": " << endl;
   do {
     cout << " " << itr->second << endl;
   ++itr;
 } while (itr != mmp.upper_bound(n));

} else

 cout << "No entry for " << n << " found." << endl;

}</source>