cplusplus.com cplusplus.com
cplusplus.com   C++ : Reference : STL Containers : map : empty
- -
C++
Information
Documentation
Reference
Articles
Sourcecode
Forum
Reference
C Library
IOstream Library
Strings library
STL Containers
STL Algorithms
STL Containers
bitset
deque
list
map
multimap
multiset
priority_queue
queue
set
stack
vector
map
comparison operators
map::map
map::~map
member functions:
· map::begin
· map::clear
· map::count
· map::empty
· map::end
· map::equal_range
· map::erase
· map::find
· map::get_allocator
· map::insert
· map::key_comp
· map::lower_bound
· map::max_size
· map::operator=
· map::operator[]
· map::rbegin
· map::rend
· map::size
· map::swap
· map::upper_bound
· map::value_comp

-

map::empty public member function
bool empty ( ) const;

Test whether container is empty

Returns whether the map container is empty, i.e. whether its size is 0.

This function does not modify the content of the container in any way. To clear its content, use member clear.

Parameters

none

Return Value

true if the container size is 0, false otherwise.

Example

// map::empty
#include <iostream>
#include <map>
using namespace std;

int main ()
{
  map<char,int> mymap;

  mymap['a']=10;
  mymap['b']=20;
  mymap['c']=30;

  while (!mymap.empty())
  {
     cout << mymap.begin()->first << " => ";
     cout << mymap.begin()->second << endl;
     mymap.erase(mymap.begin());
  }

  return 0;
}

Output:

a => 10
b => 20
c => 30

Complexity

Constant.

See also

map::clear Clear content (public member function)
map::erase Erase elements (public member function)
map::size Return container size (public member function)

© The C++ Resources Network, 2000-2007 - All rights reserved
Spotted an error? - contact us