C++ Maps

C++ Maps can be used to store key/value pairs.

begin

  iterator begin();

The function begin() returns an iterator to the first element in the map.

clear

  void clear();

The clear() function deletes all elements from the map.

count

  size_type count( const KEY_TYPE &key );

The function count() returns the number of occurrences of key in the map.

empty

  bool empty();

The function empty() returns true if the map is empty, and false otherwise.

end

  iterator end();

The end() function returns an iterator to the end of the map.

equal_range

  pair equal_range( const KEY_TYPE &key );

The function equal_range() returns two iterators - one to the first element that contains key, another to the last element that contains key.

erase

  void erase( iterator pos );
  void erase( iterator start, iterator end );
  size_type erase( const KEY_TYPE &key );

The erase function() either erases the element at pos, erases the elements between start and end, or erases all elements that have the value of key.

find

  iterator find( const KEY_TYPE &key );

The find() function returns an iterator to key, or an iterator to the end of the map if key is not found.

get_allocator

  allocator_type get_allocator();

The get_allocator() function returns the allocator of the map.

insert

  iterator insert( iterator pos, const pair<KEY_TYPE,VALUE_TYPE> &val );
  void insert( input_iterator start, input_iterator end );
  pair<iterator, bool> insert( const pair<KEY_TYPE,VALUE_TYPE> &val );

The function insert() either:

• inserts val after the element at pos, and returns an iterator to that element.
• inserts a range of elements from start to end.
• inserts val, but only if val doesn't already exist. The return value is an iterator to the element inserted, and a boolean describing whether an insertion took place.

key_comp

  key_compare key_comp();

The function key_comp() returns the function that compares keys.

lower_bound

  iterator lower_bound( const KEY_TYPE &key );

The lower_bound() function returns an iterator to the first element which has a value greater than or equal to key.

max_size

  size_type max_size();

The function max_size() returns the maximum number of elements that the map can hold.

rbegin

  reverse_iterator rbegin();

The rbegin() function returns a reverse iterator to the end of the map.

rend

  reverse_iterator rend();

The function rend() returns a reverse iterator to the start of the map.

size

  size_type size();

The function size() returns the number of elements currently in the map.

swap

  void swap( map &obj );

The swap() function exchanges the elements in obj with those in the current map.

upper_bound

  iterator upper_bound( const KEY_TYPE &key );

The function upper_bound() returns an iterator to the first element in the map with a key greater than key.

value_comp

  value_compare value_comp();

The value_comp() function returns the function that compares values.