std::multimap::multimap

参数

comp

Binary predicate that, taking two element keys as argument, returnstrueif the first argument goes before the second argument in the strict weak ordering it defines, andfalse否则为 false。
This shall be a function pointer or a function object.
成员类型key_compareis the internal comparison object type used by the container, defined in multimap as an alias of its third template parameter (Compare).
如果已知key_compareuses the default less (which has no state), this parameter is not relevant.

alloc

Allocator object.
The container keeps and uses an internal copy of this allocator.
成员类型allocator_typeis the internal allocator type used by the container, defined in multimap as an alias of its fourth template parameter (Alloc).
如果已知allocator_typeis an instantiation of the default allocator (which has no state), this parameter is not relevant.

first, last

指向范围内初始位置和最终位置的输入迭代器。 使用的范围是[first,last)，它包括first和last之间的所有元素，包括first指向的元素，但不包括last指向的元素。
函数模板参数InputIteratorshall be an input iterator type that points to elements of a type from whichvalue_typeobjects can be constructed (in multimap,value_typeis an alias ofpair<const key_type, mapped_type>)

x

Another multimap object of the same type (with the same class template arguments键, T, Compare和Alloc), whose contents are either copied or acquired.

il

il
这些对象是从初始化列表声明符自动构造的。
成员类型value_typeis the type of the elements in the container, defined in multimap as an alias ofpair<const key_type, mapped_type>(see multimap types).

示例

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// constructing multimaps
#include <iostream>
#include <map>

bool fncomp (char lhs, char rhs) {return lhs<rhs;}

struct classcomp {
  bool operator() (const char& lhs, const char& rhs) const
  {return lhs<rhs;}
};

int main ()
{
  std::multimap<char,int> first;

  first.insert(std::pair<char,int>('a',10));
  first.insert(std::pair<char,int>('b',15));
  first.insert(std::pair<char,int>('b',20));
  first.insert(std::pair<char,int>('c',25));

  std::multimap<char,int> second (first.begin(),first.end());

  std::multimap<char,int> third (second);

  std::multimap<char,int,classcomp> fourth;                 // class as Compare

  bool(*fn_pt)(char,char) = fncomp;
  std::multimap<char,int,bool(*)(char,char)> fifth (fn_pt); // function pointer as comp

  return 0;
}

复杂度

迭代器有效性

数据竞争

异常安全

另见

multimap::operator=

复制容器内容 （公开成员函数）

multimap::insert

插入元素 (公开成员函数)