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) |