Defined in header <cwctype> int iswalpha( std::wint_t ch ); Checks if the given wide character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz) or any alphabetic character specific to the current locale. Parameters ch - wide character Return value Non-zero value if the wide character is a alphabetic character, 0 otherwise. Example #include <iostream> #include &l

Usage friend specifier

Defined in header <locale> public: const CharT* scan_not( mask m, const CharT* beg, const CharT* end ) const; (1) protected: virtual const CharT* do_scan_not( mask m, const CharT* beg, const CharT* end) const; (2) 1) public member function, calls the protected virtual member function do_scan_not of the most derived class. 2) Locates the first character in the character array [beg, end) that does not satisfy the classification mask m, that is, the first character c s

(1) T operator[]( std::size_t pos ) const; (until C++11) const T& operator[]( std::size_t pos ) const; (since C++11) T& operator[]( std::size_t pos ); (2) std::valarray<T> operator[]( std::slice slicearr ) const; (3) std::slice_array<T> operator[]( std::slice slicearr ); (4) std::valarray<T> operator[]( const std::gslice& gslicearr ) const; (5) std::gslice_arr

const CharT* c_str() const; Returns a pointer to a null-terminated character array with data equivalent to those stored in the string. The pointer is such that the range [c_str(); c_str() + size()] is valid and the values in it correspond to the values stored in the string with an additional null character after the last position. The pointer obtained from c_str() may be invalidated by: Passing a non-const reference to the string to any standard library function, or Calling non-const

Defined in header <locale> class locale; An object of class std::locale is an immutable indexed set of immutable facets. Each stream object of the C++ input/output library is associated with an std::locale object and uses its facets for parsing and formatting of all data. In addition, a locale object is associated with each std::basic_regex object. Locale objects can also be used as predicates that perform string collation with the standard containers and algorithms and can

Objects, references, functions including function template specializations, and expressions have a property called type, which both restricts the operations that are permitted for those entities and provides semantic meaning to the otherwise generic sequences of bits. Type classification The C++ type system consists of the following types: fundamental types (see also std::is_fundamental): the type void (see also std::is_void); the type std::nullptr_t (see also std::is_null_pointer); a

Usage protected access specifier

(1) void erase( iterator pos ); (until C++11) iterator erase( iterator pos ); (since C++17) iterator erase( const_iterator pos ); (since C++11) (2) void erase( iterator first, iterator last ); (until C++11) iterator erase( const_iterator first, const_iterator last ); (since C++11) size_type erase( const key_type& key ); (3) Removes specified elements from the container. 1) Removes the element at pos. 2) Removes the elements in the range [first; last),

size_type size() const; size_type length() const; Returns the number of CharT elements in the string, i.e. std::distance(begin(), end()). Parameters (none). Return value The number of CharT elements in the string. Exceptions (none) (until C++11) noexcept specification: noexcept (since C++11) Complexity Constant. Notes For std::string, the elements are bytes (objects of type char), which are not the same as characters if a multibyte encoding such as UTF-8 is