Compares two string argumentss1 ands2 according to the lexicographic comparison rules defined by this locale'sstd::collate<CharT> facet. This operator allows any locale object that has a collate facet to be used as a binary predicate in the standard algorithms (such asstd::sort) and ordered containers (such asstd::set).

[edit]Parameters

[edit]Return value

true ifs1 is lexicographically less thans2,false otherwise.

[edit]Possible implementation

template<class CharT,class Traits,class Alloc>bool operator()(conststd::basic_string<CharT,Traits,Alloc>& s1,conststd::basic_string<CharT,Traits,Alloc>& s2)const{returnstd::use_facet<std::collate<CharT>>(*this).compare(               s1.data(), s1.data()+ s1.size(),               s2.data(), s2.data()+ s2.size())<0;}

[edit]Example

#include <algorithm>#include <cassert>#include <locale>#include <string>#include <vector> int main(){std::vector<std::wstring> v={L"жил", L"был", L"пёс"};std::sort(v.begin(), v.end(),std::locale("ru_RU.UTF8"));assert(v[0]== L"был");assert(v[1]== L"жил");assert(v[2]== L"пёс");}

[edit]See also

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