set
|
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A container that is optimized for
fast associative lookup. Items are matched using their operator==
. When an item is inserted into a set , the item is
stored in a data structure where it can be found quickly. Within the data
structure, the items are ordered according to a user-defined comparator function
object. A typical user-supplied function object is less
, which orders the items in ascending order. Unlike a multiset
, a set cannot contain multiple copies of the same
item.
Library
Standards<ToolKit>
Declaration
#include <set>
template< class T, class Compare, class Allocator >
class set
Interface
Constructor
set()
Constructs an empty set
that orders elements using the comparator Compare()
and using Allocator() to manage storage.
Constructor
explicit
set( const Compare& comp ,
const Allocator& alloc )
Constructs an empty set
that orders elements using comp and uses alloc
Allocator()
) to manage storage.
Constructor
set(
const T* first ,
const T* last ,
const Compare& compare ,
const Allocator& alloc )
Constructs a set that
contains copies of the elements in the range [ first
, last )
, using compare (default Compare()
) to order elements and using alloc (default Allocator()
) to manage storage.
Constructor
set(
const_iterator first ,
const_iterator last ,
const Compare& compare ,
const Allocator& alloc )
Constructs a set that
contains copies of elements in the range [ first
, last )
, using compare (default Compare()
) to order elements and using alloc (default Allocator()
) to manage storage.
Constructor
set(
const set< T, Compare, Allocator >& other
)
Constructs a set that is
a copy of other .
Destructor
~set()
Destroys the set and
erases all of its items.
=
set<
T, Compare, Allocator >& operator=( const set< T, Compare,
Allocator >& other )
Replaces the set's
contents with a copy of other 's.
begin
iterator
begin()
Returns an iterator
positioned at the first element in the set.
begin
const_iterator
begin() const
Returns a constant
iterator positioned at the first element in the set.
clear
void
clear()
Erases all of the set
elements.
count
size_type
count( const T& value )
const
Returns the number of
elements in the set that match value .
empty
bool
empty() const
Returns true
if the set contains no elements.
end
iterator
end()
Returns an iterator
positioned immediately after the last item in the set.
end
const_iterator
end() const
Returns a constant
iterator positioned immediately after the last item in the set.
equal_range
pair<
iterator, iterator > equal_range( const T& key )
Returns a pair with a
first element that is equal to lower_bound()
and a second element that is equal to upper_bound()
.
equal_range
pair<
const_iterator, const_iterator > equal_range( const T& key ) const
Returns a pair with a
first element that is equal to lower_bound()
and a second element that is equal to upper_bound()
.
erase
void
erase( iterator pos )
Erases the element at pos
.
erase
void
erase( iterator first ,
iterator last )
Erases elements in the
range [ first ,
last ) .
erase
size_type
erase( const T& value )
Erases all elements that
match value and returns the number of elements
erased.
find
iterator
find( const T& value )
If the set contains an
element that matches value , returns an iterator
positioned at the matching element. Otherwise, returns an iterator
positioned at end() .
find
const_iterator
find( const T& value )
const
If the set contains an
element that matches value , returns a constant
iterator positioned at the matching element. Otherwise, returns a constant
iterator positioned at end() .
get_allocator
Allocator
get_allocator() const
Returns a copy of the
allocator the set is using to manage storage.
insert
pair<
iterator, bool > insert( const T& value
)
If the set does not
contain an element that matches value , inserts a
copy of value and returns a pair with a first
element that is an iterator positioned at the new element and with a second
element that is true . If the set already
contains an element that matches value , returns a
pair with a first element that is an iterator positioned at the existing
element and with a second element that is false
.
insert
iterator
insert( iterator pos ,
const T& value )
Inserts a copy of value
if the set does not a contain an element that matches value
, using pos as a hint on where to start searching
for the correct place to insert.
insert
void
insert( const T* first ,
const T* last )
Inserts copies of
elements in the range [ first
, last )
.
insert
void
insert( const_iterator first ,
const_iterator last )
Inserts copies of
elements in the range [ first
, last )
.
key_comp
key_compare
key_comp() const
Returns the set's key
comparison object.
lower_bound
iterator
lower_bound( const T& value )
Returns an iterator
positioned at the first location value can be
inserted without violating the ordering criteria. If no such location is
found, returns an iterator positioned at end()
.
lower_bound
const
iterator lower_bound( const T& value )
const
Returns a constant
iterator positioned at the first location value
can be inserted without violating the ordering criteria. If no such location
is found, returns a constant iterator positioned at end()
.
max_size
size_type
max_size() const
Returns the maximum
number of entries the set can contain.
rbegin
reverse_iterator
rbegin()
Returns a reverse
iterator positioned at the last item in the set.
rbegin
const_reverse_iterator
rbegin() const
Returns a constant
reverse iterator positioned at the last item in the set.
rend
reverse_iterator
rend()
Returns a reverse
iterator positioned immediately before the first item in the set.
rend
const_reverse_iterator
rend() const
Returns a constant
reverse iterator positioned immediately before the last item in the set.
size
size_type
size() const
Returns the number of
entries the set contains.
swap
void
swap( hash_set< T, Hash, Equal, Allocator >& other
)
Exchanges the contents of
set and other .
upper_bound
iterator
upper_bound( const T& value )
Returns an iterator
positioned at the last location that does not satisfy Compare(
element , value
) . If no such location is found, returns an
iterator positioned at end() .
upper_bound
const_iterator
upper_bound( const T& value )
const
Returns a constant
iterator positioned at the last location that does not satisfy Compare(
element , value
) . If no such location is found, returns a
constant iterator positioned at end() .
value_comp
value_compare
value_comp() const
Returns the set's value
comparison object.
Non-Member Functions
==
bool
operator==( const set< T, Compare, Allocator >& x
, const set< T, Compare,
Allocator >& y )
Returns true
if x contains the same items in the same order as y
.
<
bool
operator<( const set< T, Compare, Allocator >& x
, const set< T, Compare,
Allocator >& y )
Returns true
if x is lexicographically less than y
.
swap
void
swap( set< T, Compare, Allocator >& x
, set< T, Compare, Allocator
>& y )
Exchanges the contents of
x and y .
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