std::set::set
| (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.
[first, last). if multiple elements in the range have keys that compare equivalent, it is unspecified which element is inserted (pending LWG2844)other. If alloc is not provided, allocator is obtained by calling std::allocator_traits<allocator_type>::select_on_container_copy_construction(other.get_allocator()).other using move semantics. If alloc is not provided, allocator is obtained by move-construction from the allocator belonging to other.init. if multiple elements in the range have keys that compare equivalent, it is unspecified which element is inserted (pending LWG2844)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] Notes
After container move construction (overload (4)), references, pointers, and iterators (other than the end iterator) to other remain valid, but refer to elements that are now in *this. The current standard makes this guarantee via the blanket statement in §23.2.1[container.requirements.general]/12, and a more direct guarantee is under consideration via LWG 2321.
[edit] Example
#include <iostream> #include <string> #include <set> #include <cmath> struct Point { double x, y; }; struct PointCmp { bool operator()(const Point& lhs, const Point& rhs) const { return std::hypot(lhs.x, lhs.y) < std::hypot(rhs.x, rhs.y); } }; int main() { // (1) Default constructor std::set<std::string> a; a.insert("cat"); a.insert("dog"); a.insert("horse"); for(auto& str: a) std::cout << str << ' '; std::cout << '\n'; // (2) Iterator constructor std::set<std::string> b(a.find("dog"), a.end()); for(auto& str: b) std::cout << str << ' '; std::cout << '\n'; // (3) Copy constructor std::set<std::string> c(a); c.insert("another horse"); for(auto& str: c) std::cout << str << ' '; std::cout << '\n'; // (4) Move constructor std::set<std::string> d(std::move(a)); for(auto& str: d) std::cout << str << ' '; std::cout << '\n'; std::cout << "moved-from set is "; for(auto& str: a) std::cout << str << ' '; std::cout << '\n'; // (5) Initializer list constructor std::set<std::string> e {"one", "two", "three", "five", "eight"}; for(auto& str: e) std::cout << str << ' '; std::cout << '\n'; // custom comparison std::set<Point, PointCmp> z = {{2, 5}, {3, 4}, {1, 1}}; z.insert({1, -1}); // this fails because the magnitude of 1,-1 equals 1,1 for(auto& p: z) std::cout << '(' << p.x << ',' << p.y << ") "; std::cout << '\n'; }
Output:
cat dog horse dog horse another horse cat dog horse cat dog horse moved-from set is eight five one three two (1,1) (3,4) (2,5)
[edit] See also
| assigns values to the container (public member function) |