std::set::set
From cppreference.com
(1) | ||
explicit set( const Compare& comp = Compare(),
const Allocator& alloc = Allocator() ); |
(until C++14) | |
set() : set( Compare() ) {}
explicit set( const Compare& comp, |
(since C++14) | |
explicit set( const Allocator& alloc );
|
(1) | (since C++11) |
(2) | ||
template< class InputIt >
set( InputIt first, InputIt last, |
||
template< class InputIt >
set( InputIt first, InputIt last, const Allocator& alloc) |
(since C++14) | |
set( const set& other );
|
(3) | |
set( const set& other, const Allocator& alloc );
|
(3) | (since C++11) |
set( set&& other );
|
(4) | (since C++11) |
set( set&& other, const Allocator& alloc );
|
(4) | (since C++11) |
(5) | ||
set( std::initializer_list<value_type> init,
const Compare& comp = Compare(), |
(since C++11) | |
set( std::initializer_list<value_type> init, const Allocator& alloc )
: set(init, Compare(), alloc) {} |
(since C++14) | |
Constructs new container from a variety of data sources and optionally using user supplied allocator alloc
or comparison function object comp
.
1) Default constructor. Constructs empty container.
2) Range constructor. Constructs the container with the contents of the range
[first, last)
.
3) Copy constructor. Constructs the container with the copy of the contents of
other
. If alloc
is not provided, allocator is obtained by calling std::allocator_traits<allocator_type>::select_on_container_copy_construction(other.get_allocator()).
4) Move constructor. Constructs the container with the contents of
other
using move semantics. If alloc
is not provided, allocator is obtained by move-construction from the allocator belonging to other
.
5) Initializer-list constructor. Constructs the container with the contents of the initializer list
init
.
Contents |
[edit] Parameters
alloc | - | allocator to use for all memory allocations of this container |
comp | - | comparison function object to use for all comparisons of keys |
first, last | - | the range to copy the elements from |
other | - | another container to be used as source to initialize the elements of the container with |
init | - | initializer list to initialize the elements of the container with |
Type requirements | ||
-
InputIt must meet the requirements of InputIterator .
|
||
-
Compare must meet the requirements of Compare .
|
||
-
Allocator must meet the requirements of Allocator .
|
[edit] Complexity
1) Constant
2) N log(N) where N = std::distance(first, last) in general, linear in N
if the range is already sorted by value_comp()
.
3) Linear in size of other
4) Constant. If alloc
is given and alloc != other.get_allocator(), then linear.
5) N log(N) where N = init.size()) in general, linear in N
if init
is already sorted by value_comp()
.
[edit] Example
Run this code
#include <iostream> #include <string> #include <set> // Helper function for printing pairs. template<class Ch, class Tr, class A, class B> inline std::basic_ostream<Ch, Tr>& operator<<(std::basic_ostream<Ch, Tr>& stream, std::pair<A,B> p) { return stream << '(' << p.first << ", " << p.second << ')'; } // Helper function for printing containers. template<class Ch, class Tr, class Co> std::basic_ostream<Ch, Tr>& operator<<(std::basic_ostream<Ch, Tr>& stream, Co& c) { stream << '{' << *c.begin(); for(auto it = ++(c.begin()); it != c.end(); ++it) stream << ", " << *it; stream << '}' << std::endl; return stream; } int main() { // (1) Default constructor std::set<std::string> a; a.insert("something"); a.insert("anything"); a.insert("that thing"); std::cout << "a = " << a; // (2) Iterator constructor std::set<std::string> b(a.find("anything"), a.end()); std::cout << std::string(80, '-') << std::endl; std::cout << "b = " << b; // (3) Copy constructor std::set<std::string> c(a); c.insert("another thing"); std::cout << std::string(80, '-') << std::endl; std::cout << "a = " << a; std::cout << "c = " << c; // (4) Move constructor std::set<std::string> d(std::move(a)); std::cout << std::string(80, '-') << std::endl; std::cout << "a = nullptr" << std::endl; std::cout << "d = " << d; // (5) Initializer list constructor std::set<std::string> e{ "one", "two", "three", "five", "eight" }; std::cout << std::string(80, '-') << std::endl; std::cout << "e = " << e; }
Output:
a = {anything, something, that thing} -------------------------------------------------------------------------------- b = {anything, something, that thing} -------------------------------------------------------------------------------- a = {anything, something, that thing} c = {another thing, anything, something, that thing} -------------------------------------------------------------------------------- a = nullptr d = {anything, something, that thing} -------------------------------------------------------------------------------- e = {eight, five, one, three, two}
[edit] See also
assigns values to the container (public member function) |