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<regex> operators

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operator!=
operator>
operator>=
operator<
operator<<
operator<=
operator==

operator!=

Not 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);

Parameters

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.

Remarks

Each template operator returns !(left == right).

Example

// std__regex__operator_ne.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 == false
sub != sub == false
string("aab") != sub == true
sub != string("aab") == true
"aab" != sub == true
sub != "aab" == true
'a' != sub == true
sub != 'a' == true

operator<

Less than 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);

Parameters

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.

Remarks

Each template operator converts its arguments to a string type and returns true only if the converted value of left compares less than the converted value of right.

Example

// std__regex__operator_lt.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 << "sub == " << sub << std::endl;
    std::cout << 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);
    }

sub == aaa

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

operator<<

Inserts a sub_match in a stream.

template <class Elem, class IOtraits, class Alloc, class BidIt>
basic_ostream<Elem, IOtraits>& operator<<(basic_ostream<Elem, IOtraits>& os,
    const sub_match<BidIt>& right);

Parameters

Elem
The element type.

IOtraits
The string traits class.

Alloc
The allocator class.

BidIt
The iterator type.

os
The output stream.

right
The object to insert.

Remarks

The template operator returns os << right.str().

Example

// std__regex__operator_ins.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[0];
    std::cout << "whole match: " << sub << std::endl;

    return (0);
    }

whole match: caaa

operator<=

Less than or 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);

Parameters

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.

Remarks

Each template operator returns !(right < left).

Example

// std__regex__operator_le.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 << "sub == " << sub << std::endl;
    std::cout << 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);
    }

sub == aaa

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

operator==

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);

Parameters

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.

Remarks

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 class template match_results or sub_match are converted by calling the str member function;

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

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

Example

// std__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

operator>

Greater than 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);

Parameters

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.

Remarks

Each template operator returns right < left.

Example

// std__regex__operator_gt.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 << "sub == " << sub << std::endl;
    std::cout << 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);
    }

sub == aaa

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

operator>=

Greater than or 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);

Parameters

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.

Remarks

Each template operator returns !(left < right).

Example

// std__regex__operator_ge.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 << "sub == " << sub << std::endl;
    std::cout << 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);
    }

sub == aaa

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

See also

<regex>
regex_constants Class
regex_error Class
<regex> functions
regex_iterator Class
regex_token_iterator Class
regex_traits Class
<regex> typedefs