使用boost :: assign和一个std :: set嵌套在一个std :: map [英] using boost::assign with a std::set nested inside a std::map
问题描述
我试图使用 boost :: assign
来模拟 std :: map的C ++ 11初始化
包含 std :: set
。
I am trying to use boost::assign
to emulate C++11 initialization of a std::map
containing a std::set
.
#include <set>
#include <map>
#include <stdint.h>
#include <boost/assign/list_of.hpp>
typedef std::map< uint32_t, std::set< uint32_t> > the_map_t;
the_map_t data = boost::assign::map_list_of( 1, boost::assign::list_of(10)(20)(30) )
( 2, boost::assign::list_of(12)(22)(32) )
( 3, boost::assign::list_of(13)(23)(33) )
( 4, boost::assign::list_of(14)(24)(34) );
初始化 std :: set
code> boost :: assign :: list_of 在自己使用时可以正常工作,但是当我尝试上面的代码时,赋值是不明确的,在 std :: set
的构造函数被调用:
Initialisation of std::set
using boost::assign::list_of
works as expected when used on its own, but when I try the above code the assignment is ambiguous at the point where the std::set
's constructor is called:
map-assign.cpp:16: instantiated from here
include/c++/4.4.6/bits/stl_pair.h:101: error: call of overloaded set(const boost::assign_detail::generic_list<int>&) is ambiguous
include/c++/4.4.6/bits/stl_set.h:188: note: candidates are:
std::set<_Key, _Compare, _Alloc>::set(
const std::set<_Key, _Compare, _Alloc>&)
[with _Key = unsigned int, _Compare = std::less<unsigned int>, _Alloc = std::allocator<unsigned int>]
include/c++/4.4.6/bits/stl_set.h:145: note:
std::set<_Key, _Compare, _Alloc>::set(
const _Compare&, const _Alloc&)
[with _Key = unsigned int, _Compare = std::less<unsigned int>, _Alloc = std::allocator<unsigned int>]
如何解决此歧义错误?
推荐答案
c> boost :: assign :: map_list_of 需要第二个模板参数的提示 - < uint32_t,std :: set< uint32_t> >
。因此行
In this case boost::assign::map_list_of
needs a hint for second template argument - <uint32_t, std::set< uint32_t> >
. Therefore line
the_map_t data = boost::assign::map_list_of(...);
成为
the_map_t data = boost::assign::map_list_of<uint32_t, std::set< uint32_t> >(...);
这篇关于使用boost :: assign和一个std :: set嵌套在一个std :: map的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!