operator== <regex>

Equal comparison for various objects.

template<class BidIt>
    bool operator==(const sub_match<BidIt>& left,
        const sub_match<BidIt>& right);
template<class BidIt, class IOtraits, class Alloc>
    bool operator==(
        const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& left,
        const sub_match<BidIt>& right);
template<class BidIt, class IOtraits, class Alloc>
    bool operator==(const sub_match<BidIt>& left,
        const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& right);
template<class BidIt>
    bool operator==(const typename iterator_traits<BidIt>::value_type* left,
        const sub_match<BidIt>& right);
template<class BidIt>
    bool operator==(const sub_match<BidIt>& left,
        const typename iterator_traits<BidIt>::value_type* right);
template<class BidIt>
    bool operator==(const typename iterator_traits<BidIt>::value_type& left,
        const sub_match<BidIt>& right);
template<class BidIt>
    bool operator==(const sub_match<BidIt>& left,
        const typename iterator_traits<BidIt>::value_type& right);
template<class BidIt, class Alloc>
    bool operator==(const match_results<BidIt, Alloc>& left,
        const match_results<BidIt, Alloc>& right);

BidIt

The iterator type.

IOtraits

The string traits class.

Alloc

The allocator class.

left

The left object to compare.

right

The right object to compare.

Each template operator converts each of its arguments to a string type and returns the result of comparing the converted objects for equality.

When a template operator converts its arguments to a string type it uses the first of the following transformations that applies:

arguments whose types are a specialization of template class match_results or sub_match are converted by calling the str member function;

arguments whose types are a specialization of the template class basic_string are unchanged;

all other argument types are converted by passing the argument value to the constructor for an appropriate specialization of the template class basic_string.

 

// std_tr1__regex__operator_eq.cpp 
// compile with: /EHsc 
#include <regex> 
#include <iostream> 
 
typedef std::cmatch::string_type Mystr; 
int main() 
    { 
    std::regex rx("c(a*)|(b)"); 
    std::cmatch mr; 
 
    std::regex_search("xcaaay", mr, rx); 
 
    std::csub_match sub = mr[1]; 
    std::cout << "match == " << mr.str() << std::endl; 
    std::cout << "sub == " << sub << std::endl; 
    std::cout << std::endl; 
 
    std::cout << "match == match == " << std::boolalpha 
        << (mr == mr) << std::endl; 
    std::cout << "sub == sub == " << std::boolalpha 
        << (sub == sub) << std::endl; 
 
    std::cout << "string(\"aab\") == sub == " << std::boolalpha 
        << (Mystr("aab") == sub) << std::endl; 
    std::cout << "sub == string(\"aab\") == " << std::boolalpha 
        << (sub == Mystr("aab")) << std::endl; 
 
    std::cout << "\"aab\" == sub == " << std::boolalpha 
        << ("aab" == sub) << std::endl; 
    std::cout << "sub == \"aab\" == " << std::boolalpha 
        << (sub == "aab") << std::endl; 
 
    std::cout << "'a' == sub == " << std::boolalpha 
        << ('a' == sub) << std::endl; 
    std::cout << "sub == 'a' == " << std::boolalpha 
        << (sub == 'a') << std::endl; 
 
    return (0); 
    } 
 
match == caaa
sub == aaa

match == match == true
sub == sub == true
string("aab") == sub == false
sub == string("aab") == false
"aab" == sub == false
sub == "aab" == false
'a' == sub == false
sub == 'a' == false

Header: <regex>

Namespace: std

Was this page helpful?
(1500 characters remaining)
Thank you for your feedback
Show:
© 2014 Microsoft