C++/Map Multimap/map update

Update a key value

<source lang="cpp">

/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

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

using namespace std; int main() {

   /* create map / associative array
    * - keys are strings
    * - values are floats
    */
   typedef map<string,float> StringFloatMap;
   StringFloatMap stocks;      // create empty container
   // insert some elements
   stocks["BASF"] = 369.50;
   stocks["VW"] = 413.50;
   stocks["Daimler"] = 819.00;
   stocks["BMW"] = 834.00;
   stocks["Siemens"] = 842.20;
   // print all elements
   StringFloatMap::iterator pos;
   for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
       cout << "stock: " << pos->first << "\t"
            << "price: " << pos->second << endl;
   }
   cout << endl;

   /* rename key from "VW" to "Volkswagen"
    * - only provided by exchanging element
    */
   stocks["Volkswagen"] = stocks["VW"];

   // print all elements
   for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
       cout << "stock: " << pos->first << "\t"
            << "price: " << pos->second << endl;
   }
   cout << endl;

} /* stock: BASF price: 369.5 stock: BMW price: 834 stock: Daimler price: 819 stock: Siemens price: 842.2 stock: VW price: 413.5 stock: BASF price: 369.5 stock: BMW price: 834 stock: Daimler price: 819 stock: Siemens price: 842.2 stock: VW price: 413.5 stock: Volkswagen price: 413.5

*/
       
   
 </source>

Use push_back to add object to vector

<source lang="cpp">

1. include <algorithm>
2. include <functional>
3. include <iomanip>
4. include <iostream>
5. include <map>
6. include <string>
7. include <utility>
8. include <vector>

using namespace std; class PC{

  public:
  enum PC_type { Dell, HP, IBM, Compaq };
  PC( PC_type appliance = Dell, int model = 220,int serial = 0 );
  bool operator<( const PC& rhs ) const;
  PC_type appliance() const;
  int model() const;
  string name() const;
  void print() const;
  int serial() const;
  private:
  PC_type appliance_;
  int model_;
  int serial_;

}; inline PC::PC( PC::PC_type appliance, int model,

  int serial )
  : appliance_( appliance ), model_( model ), serial_( serial )

{} inline bool PC::operator<( const PC& rhs ) const { return appliance() < rhs.appliance() ||

  ( appliance() == rhs.appliance() && model() < rhs.model() );

} inline PC::PC_type PC::appliance() const { return appliance_; } inline int PC::model() const { return model_; } string PC::name() const {

  string what;
  switch( appliance() )
  {
     case Dell:    what = "Dell";              break;
     case HP:      what = "HP";                break;
     case IBM:     what = "IBM";               break;
     case Compaq:  what = "Compaq";            break;
     default:      what = "Unknown appliance"; break;
  }
  return what;

} inline void PC::print() const {

  char oldfill = cout.fill();
  cout << name() << " - Model "
       << model() << ", Serial number " 
       << serial() << endl;

} inline int PC::serial() const { return serial_; } bool greater_model( const pair<PC::PC_type,PC> p,int min_model ); int main( ) {

  const PC::PC_type kind[] = { PC::IBM,PC::Dell,PC::HP };
  vector<PC> v;
  for( int i = 0; i < 3; ++i )
     v.push_back( PC( kind[i], i, i ) );

}

 </source>