std::multimap::multimap

	(1)
explicit multimap( const Compare& comp = Compare(), const Allocator& alloc = Allocator() );	(until C++14)
multimap() : multimap( Compare() ) {} explicit multimap( const Compare& comp, const Allocator& alloc = Allocator() );	(since C++14)
explicit multimap( const Allocator& alloc );	(1)	(since C++11)
	(2)
template< class InputIterator > multimap( InputIterator first, InputIterator last, const Compare& comp = Compare(), const Allocator& alloc = Allocator() );
template< class InputIterator > multimap( InputIterator first, InputIterator last, const Allocator& alloc );	(since C++14)
multimap( const multimap& other );	(3)
multimap( const multimap& other, const Allocator& alloc );	(3)	(since C++11)
multimap( multimap&& other );	(4)	(since C++11)
multimap( multimap&& other, const Allocator& alloc );	(4)	(since C++11)
	(5)
multimap( std::initializer_list<value_type> init, const Compare& comp = Compare(), const Allocator& alloc = Allocator() );	(since C++11)
multimap( std::initializer_list<value_type> init, const Allocator& );	(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构造包含范围内容的容器。[first, last)...

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。的内容构造容器。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使用初始化程序列表的内容构造容器。init...

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

-输入器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。

复杂性

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 <map>
 
struct Point { double x, y; };
struct PointCmp {
    bool operator()(const Point& lhs, const Point& rhs) const { 
        return lhs.x < rhs.x; // NB. ignores y on purpose
    }
};
 
int main() {
    std::multimap<int, int> m = {{1,1},{2,2},{3,3},{4,4},{5,5},{4,4},{3,3},{2,2},{1,1}};
    for(auto& p: m) std::cout << p.first << ' ' << p.second << '\n';
 
    // custom comparison
    std::multimap<Point, double, PointCmp> mag{
        { {5, 12}, 13 },
        { {3, 4}, 5 },
        { {8, 15}, 17 },
        { {3, -3}, -1 },
    };
 
  for(auto p : mag)
      std::cout << "The magnitude of (" << p.first.x
                << ", " << p.first.y << ") is "
                << p.second << '\n';
}

二次

产出：

二次

1 1
1 1
2 2
2 2
3 3
3 3
4 4
4 4
5 5
The magnitude of (3, 4) is 5
The magnitude of (3, -3) is -1
The magnitude of (5, 12) is 13
The magnitude of (8, 15) is 17

二次

另见

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

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最后更新于：2017-12-18