std::set::set

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, const Allocator& alloc = Allocator()	(since C++14)
explicit set( const Allocator& alloc	(1)	(since C++11)
	(2)
template< class InputIt > set( InputIt first, InputIt last, const Compare& comp = Compare(), const Allocator& alloc = Allocator()
template< class InputIt > set( InputIt first, InputIt last, const Allocator& alloc) : set(first, last, Compare(), 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(), const Allocator& alloc = Allocator()	(since C++11)
set( std::initializer_list<value_type> init, const Allocator& alloc ) : set(init, Compare(), alloc) {}	(since C++14)

从各种数据源构造新容器，并可选择使用用户提供的分配器。alloc或比较函数对象comp...

1%29默认构造函数.构造空容器。

2%29范围构造函数。使用范围的内容构造容器。[first, last)如果区域中的多个元素具有比较等效的键，则未指定插入了%28挂起的元素。LWG2844%29

3%29复制构造函数的内容的副本构造容器。other.如果alloc不提供，则通过调用std::allocator_traits<allocator_type>::select_on_container_copy_construction(other.get_allocator())...

4%29移动构造函数.构造具有以下内容的容器other使用移动语义。如果alloc如果不提供分配器，则通过移动构造从属于other...

5%29初始项-列表构造函数使用初始化程序列表的内容构造容器。init如果区域中的多个元素具有比较等效的键，则未指定插入了%28挂起的元素。LWG2844%29

参数

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

类型要求

-输入必须符合输入器的要求。

-比较必须符合比较的要求。

-分配器必须符合分配器的要求。

1%29常数。

2%29N日志%28N%29N =std::distance(first, last)一般情况下，线性在N如果范围已经按value_comp()...

3%29线性other...

4%29常数。如果alloc被赋予和alloc != other.get_allocator()，然后是线性的。

5%29N日志%28N%29N = init.size())一般情况下，线性在N如果init已按value_comp()...

注记

在容器移动构造%28重载%284%29%29之后，引用、指针和迭代器%28---other保持有效，但引用当前在*this.现行标准通过第23.2.1节中的总括声明作出这一保证。集装箱。所需经费/12，目前正在考虑通过以下方式提供更直接的担保：lwg 2321...

例

二次

#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';
}

二次

产出：

二次

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)

二次

另见

operator=	assigns values to the container (public member function)

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