Defined in header <type_traits> template< class Base, class Derived > struct is_base_of; (since C++11) If Derived is derived from Base or if both are the same non-union class, provides the member constant value equal to true. Otherwise value is false. If both Base and Derived are non-union class types, and they are not the same type (ignoring cv-qualification), Derived shall be a complete type; otherwise the behavior is undefined. Helper variable template templa

Defined in header <type_traits> template< class T, class U > struct is_assignable; (1) (since C++11) template< class T, class U > struct is_trivially_assignable; (2) (since C++11) template< class T, class U > struct is_nothrow_assignable; (3) (since C++11) 1) If the expression std::declval<T>() = std::declval<U>() is well-formed in unevaluated context, provides the member constant value equal true. Otherwise, value is false. Access

Defined in header <type_traits> template< class T > struct is_array; (since C++11) Checks whether T is an array type. Provides the member constant value which is equal to true, if T is an array type. Otherwise, value is equal to false. Template parameters T - a type to check Helper variable template template< class T > constexpr bool is_array_v = is_array<T>::value; (since C++17) Inherited from std::integral_constant Member con

Defined in header <type_traits> template< class T > struct is_arithmetic; (since C++11) If T is an arithmetic type (that is, an integral type or a floating-point type), provides the member constant value equal true. For any other type, value is false. Template parameters T - a type to check Helper variable template template< class T > constexpr bool is_arithmetic_v = is_arithmetic<T>::value; (since C++17) Inherited from std::inte

Defined in header <type_traits> template< class T > struct is_abstract; (since C++11) If T is an abstract class (that is, a non-union class that declares or inherits at least one pure virtual function), provides the member constant value equal true. For any other type, value is false. If T is a non-union class type, T shall be a complete type; otherwise, the behavior is undefined. Template parameters T - a type to check Helper variable template templa

Defined in header <locale> template< class charT > bool isxdigit( charT ch, const locale& loc ); Checks if the given character is classified as a hexadecimal digit by the given locale's std::ctype facet. Parameters ch - character loc - locale Return value Returns true if the character is classified as a hexadecimal digit, false otherwise. Possible implementation template< class charT > bool isxdigit( charT ch, const std::locale& l

Defined in header <cctype> int isxdigit( int ch ); Checks if the given wide character is a hexadecimal numeric character (0123456789abcdefABCDEF). The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF. Parameters ch - character to classify Return value Non-zero value if the character is an hexadecimal numeric character, zero otherwise. Notes isdigit and isxdigit are the only standard narrow character clas

Defined in header <cwctype> int iswxdigit( wint_t ch ); Checks if the given wide character corresponds (if narrowed) to a hexadecimal numeric character, i.e. one of 0123456789abcdefABCDEF. Parameters ch - wide character Return value Non-zero value if the wide character is a hexadecimal numeric character, zero otherwise. Notes std::iswdigit and std::iswxdigit are the only standard wide character classification functions that are not affected by the currently

Defined in header <cwctype> int iswupper( std::wint_t ch ); Checks if the given wide character is an uppercase letter, i.e. one of ABCDEFGHIJKLMNOPQRSTUVWXYZ or any uppercase letter specific to the current locale. Parameters ch - wide character Return value Non-zero value if the wide character is an uppercase letter, zero otherwise. Example #include <iostream> #include <cwctype> #include <clocale> int main() { wchar_t c = L'\u053d'

Defined in header <cwctype> int iswspace( wint_t ch ); Checks if the given wide character is a wide whitespace character as classified by the currently installed C locale. In the default locale, the whitespace characters are the following: space (0x20, ' ') form feed (0x0c, '\f') line feed (0x0a, '\n') carriage return (0x0d, '\r') horizontal tab (0x09, '\t') vertical tab (0x0b, '\v') Parameters ch - wide character Return value Non-zero value if t