23 Strings library [strings]

23.4 String classes [string.classes]

23.4.3 Class template basic_string [basic.string]

23.4.3.1 General [basic.string.general]

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The class template basic_string describes objects that can store a sequence consisting of a varying number of arbitrary char-like objects with the first element of the sequence at position zero.
Such a sequence is also called a “string” if the type of the char-like objects that it holds is clear from context.
In the rest of [basic.string], the type of the char-like objects held in a basic_string object is designated by charT.
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A specialization of basic_string is a contiguous container ([container.reqmts]).
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In all cases, [data(), data() + size()] is a valid range, data() + size() points at an object with value charT() (a “null terminator”), and size() <= capacity() is true.
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namespace std { template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT>> class basic_string { public: // types using traits_type = traits; using value_type = charT; using allocator_type = Allocator; using size_type = typename allocator_traits<Allocator>::size_type; using difference_type = typename allocator_traits<Allocator>::difference_type; using pointer = typename allocator_traits<Allocator>::pointer; using const_pointer = typename allocator_traits<Allocator>::const_pointer; using reference = value_type&; using const_reference = const value_type&; using iterator = implementation-defined; // see [container.requirements] using const_iterator = implementation-defined; // see [container.requirements] using reverse_iterator = std::reverse_iterator<iterator>; using const_reverse_iterator = std::reverse_iterator<const_iterator>; static constexpr size_type npos = size_type(-1); // [string.cons], construct/copy/destroy constexpr basic_string() noexcept(noexcept(Allocator())) : basic_string(Allocator()) { } constexpr explicit basic_string(const Allocator& a) noexcept; constexpr basic_string(const basic_string& str); constexpr basic_string(basic_string&& str) noexcept; constexpr basic_string(const basic_string& str, size_type pos, const Allocator& a = Allocator()); constexpr basic_string(const basic_string& str, size_type pos, size_type n, const Allocator& a = Allocator()); constexpr basic_string(basic_string&& str, size_type pos, const Allocator& a = Allocator()); constexpr basic_string(basic_string&& str, size_type pos, size_type n, const Allocator& a = Allocator()); template<class T> constexpr basic_string(const T& t, size_type pos, size_type n, const Allocator& a = Allocator()); template<class T> constexpr explicit basic_string(const T& t, const Allocator& a = Allocator()); constexpr basic_string(const charT* s, size_type n, const Allocator& a = Allocator()); constexpr basic_string(const charT* s, const Allocator& a = Allocator()); basic_string(nullptr_t) = delete; constexpr basic_string(size_type n, charT c, const Allocator& a = Allocator()); template<class InputIterator> constexpr basic_string(InputIterator begin, InputIterator end, const Allocator& a = Allocator()); template<container-compatible-range<charT> R> constexpr basic_string(from_range_t, R&& rg, const Allocator& a = Allocator()); constexpr basic_string(initializer_list<charT>, const Allocator& = Allocator()); constexpr basic_string(const basic_string&, const Allocator&); constexpr basic_string(basic_string&&, const Allocator&); constexpr ~basic_string(); constexpr basic_string& operator=(const basic_string& str); constexpr basic_string& operator=(basic_string&& str) noexcept(allocator_traits<Allocator>::propagate_on_container_move_assignment::value || allocator_traits<Allocator>::is_always_equal::value); template<class T> constexpr basic_string& operator=(const T& t); constexpr basic_string& operator=(const charT* s); basic_string& operator=(nullptr_t) = delete; constexpr basic_string& operator=(charT c); constexpr basic_string& operator=(initializer_list<charT>); // [string.iterators], iterators constexpr iterator begin() noexcept; constexpr const_iterator begin() const noexcept; constexpr iterator end() noexcept; constexpr const_iterator end() const noexcept; constexpr reverse_iterator rbegin() noexcept; constexpr const_reverse_iterator rbegin() const noexcept; constexpr reverse_iterator rend() noexcept; constexpr const_reverse_iterator rend() const noexcept; constexpr const_iterator cbegin() const noexcept; constexpr const_iterator cend() const noexcept; constexpr const_reverse_iterator crbegin() const noexcept; constexpr const_reverse_iterator crend() const noexcept; // [string.capacity], capacity constexpr size_type size() const noexcept; constexpr size_type length() const noexcept; constexpr size_type max_size() const noexcept; constexpr void resize(size_type n, charT c); constexpr void resize(size_type n); template<class Operation> constexpr void resize_and_overwrite(size_type n, Operation op); constexpr size_type capacity() const noexcept; constexpr void reserve(size_type res_arg); constexpr void shrink_to_fit(); constexpr void clear() noexcept; [[nodiscard]] constexpr bool empty() const noexcept; // [string.access], element access constexpr const_reference operator[](size_type pos) const; constexpr reference operator[](size_type pos); constexpr const_reference at(size_type n) const; constexpr reference at(size_type n); constexpr const charT& front() const; constexpr charT& front(); constexpr const charT& back() const; constexpr charT& back(); // [string.modifiers], modifiers constexpr basic_string& operator+=(const basic_string& str); template<class T> constexpr basic_string& operator+=(const T& t); constexpr basic_string& operator+=(const charT* s); constexpr basic_string& operator+=(charT c); constexpr basic_string& operator+=(initializer_list<charT>); constexpr basic_string& append(const basic_string& str); constexpr basic_string& append(const basic_string& str, size_type pos, size_type n = npos); template<class T> constexpr basic_string& append(const T& t); template<class T> constexpr basic_string& append(const T& t, size_type pos, size_type n = npos); constexpr basic_string& append(const charT* s, size_type n); constexpr basic_string& append(const charT* s); constexpr basic_string& append(size_type n, charT c); template<class InputIterator> constexpr basic_string& append(InputIterator first, InputIterator last); template<container-compatible-range<charT> R> constexpr basic_string& append_range(R&& rg); constexpr basic_string& append(initializer_list<charT>); constexpr void push_back(charT c); constexpr basic_string& assign(const basic_string& str); constexpr basic_string& assign(basic_string&& str) noexcept(allocator_traits<Allocator>::propagate_on_container_move_assignment::value || allocator_traits<Allocator>::is_always_equal::value); constexpr basic_string& assign(const basic_string& str, size_type pos, size_type n = npos); template<class T> constexpr basic_string& assign(const T& t); template<class T> constexpr basic_string& assign(const T& t, size_type pos, size_type n = npos); constexpr basic_string& assign(const charT* s, size_type n); constexpr basic_string& assign(const charT* s); constexpr basic_string& assign(size_type n, charT c); template<class InputIterator> constexpr basic_string& assign(InputIterator first, InputIterator last); template<container-compatible-range<charT> R> constexpr basic_string& assign_range(R&& rg); constexpr basic_string& assign(initializer_list<charT>); constexpr basic_string& insert(size_type pos, const basic_string& str); constexpr basic_string& insert(size_type pos1, const basic_string& str, size_type pos2, size_type n = npos); template<class T> constexpr basic_string& insert(size_type pos, const T& t); template<class T> constexpr basic_string& insert(size_type pos1, const T& t, size_type pos2, size_type n = npos); constexpr basic_string& insert(size_type pos, const charT* s, size_type n); constexpr basic_string& insert(size_type pos, const charT* s); constexpr basic_string& insert(size_type pos, size_type n, charT c); constexpr iterator insert(const_iterator p, charT c); constexpr iterator insert(const_iterator p, size_type n, charT c); template<class InputIterator> constexpr iterator insert(const_iterator p, InputIterator first, InputIterator last); template<container-compatible-range<charT> R> constexpr iterator insert_range(const_iterator p, R&& rg); constexpr iterator insert(const_iterator p, initializer_list<charT>); constexpr basic_string& erase(size_type pos = 0, size_type n = npos); constexpr iterator erase(const_iterator p); constexpr iterator erase(const_iterator first, const_iterator last); constexpr void pop_back(); constexpr basic_string& replace(size_type pos1, size_type n1, const basic_string& str); constexpr basic_string& replace(size_type pos1, size_type n1, const basic_string& str, size_type pos2, size_type n2 = npos); template<class T> constexpr basic_string& replace(size_type pos1, size_type n1, const T& t); template<class T> constexpr basic_string& replace(size_type pos1, size_type n1, const T& t, size_type pos2, size_type n2 = npos); constexpr basic_string& replace(size_type pos, size_type n1, const charT* s, size_type n2); constexpr basic_string& replace(size_type pos, size_type n1, const charT* s); constexpr basic_string& replace(size_type pos, size_type n1, size_type n2, charT c); constexpr basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str); template<class T> constexpr basic_string& replace(const_iterator i1, const_iterator i2, const T& t); constexpr basic_string& replace(const_iterator i1, const_iterator i2, const charT* s, size_type n); constexpr basic_string& replace(const_iterator i1, const_iterator i2, const charT* s); constexpr basic_string& replace(const_iterator i1, const_iterator i2, size_type n, charT c); template<class InputIterator> constexpr basic_string& replace(const_iterator i1, const_iterator i2, InputIterator j1, InputIterator j2); template<container-compatible-range<charT> R> constexpr basic_string& replace_with_range(const_iterator i1, const_iterator i2, R&& rg); constexpr basic_string& replace(const_iterator, const_iterator, initializer_list<charT>); constexpr size_type copy(charT* s, size_type n, size_type pos = 0) const; constexpr void swap(basic_string& str) noexcept(allocator_traits<Allocator>::propagate_on_container_swap::value || allocator_traits<Allocator>::is_always_equal::value); // [string.ops], string operations constexpr const charT* c_str() const noexcept; constexpr const charT* data() const noexcept; constexpr charT* data() noexcept; constexpr operator basic_string_view<charT, traits>() const noexcept; constexpr allocator_type get_allocator() const noexcept; template<class T> constexpr size_type find(const T& t, size_type pos = 0) const noexcept(see below); constexpr size_type find(const basic_string& str, size_type pos = 0) const noexcept; constexpr size_type find(const charT* s, size_type pos, size_type n) const; constexpr size_type find(const charT* s, size_type pos = 0) const; constexpr size_type find(charT c, size_type pos = 0) const noexcept; template<class T> constexpr size_type rfind(const T& t, size_type pos = npos) const noexcept(see below); constexpr size_type rfind(const basic_string& str, size_type pos = npos) const noexcept; constexpr size_type rfind(const charT* s, size_type pos, size_type n) const; constexpr size_type rfind(const charT* s, size_type pos = npos) const; constexpr size_type rfind(charT c, size_type pos = npos) const noexcept; template<class T> constexpr size_type find_first_of(const T& t, size_type pos = 0) const noexcept(see below); constexpr size_type find_first_of(const basic_string& str, size_type pos = 0) const noexcept; constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const; constexpr size_type find_first_of(const charT* s, size_type pos = 0) const; constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept; template<class T> constexpr size_type find_last_of(const T& t, size_type pos = npos) const noexcept(see below); constexpr size_type find_last_of(const basic_string& str, size_type pos = npos) const noexcept; constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const; constexpr size_type find_last_of(const charT* s, size_type pos = npos) const; constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept; template<class T> constexpr size_type find_first_not_of(const T& t, size_type pos = 0) const noexcept(see below); constexpr size_type find_first_not_of(const basic_string& str, size_type pos = 0) const noexcept; constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const; constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const; constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept; template<class T> constexpr size_type find_last_not_of(const T& t, size_type pos = npos) const noexcept(see below); constexpr size_type find_last_not_of(const basic_string& str, size_type pos = npos) const noexcept; constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const; constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const; constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept; constexpr basic_string substr(size_type pos = 0, size_type n = npos) const &; constexpr basic_string substr(size_type pos = 0, size_type n = npos) &&; template<class T> constexpr int compare(const T& t) const noexcept(see below); template<class T> constexpr int compare(size_type pos1, size_type n1, const T& t) const; template<class T> constexpr int compare(size_type pos1, size_type n1, const T& t, size_type pos2, size_type n2 = npos) const; constexpr int compare(const basic_string& str) const noexcept; constexpr int compare(size_type pos1, size_type n1, const basic_string& str) const; constexpr int compare(size_type pos1, size_type n1, const basic_string& str, size_type pos2, size_type n2 = npos) const; constexpr int compare(const charT* s) const; constexpr int compare(size_type pos1, size_type n1, const charT* s) const; constexpr int compare(size_type pos1, size_type n1, const charT* s, size_type n2) const; constexpr bool starts_with(basic_string_view<charT, traits> x) const noexcept; constexpr bool starts_with(charT x) const noexcept; constexpr bool starts_with(const charT* x) const; constexpr bool ends_with(basic_string_view<charT, traits> x) const noexcept; constexpr bool ends_with(charT x) const noexcept; constexpr bool ends_with(const charT* x) const; constexpr bool contains(basic_string_view<charT, traits> x) const noexcept; constexpr bool contains(charT x) const noexcept; constexpr bool contains(const charT* x) const; }; template<class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>> basic_string(InputIterator, InputIterator, Allocator = Allocator()) -> basic_string<typename iterator_traits<InputIterator>::value_type, char_traits<typename iterator_traits<InputIterator>::value_type>, Allocator>; template<ranges::input_range R, class Allocator = allocator<ranges::range_value_t<R>>> basic_string(from_range_t, R&&, Allocator = Allocator()) -> basic_string<ranges::range_value_t<R>, char_traits<ranges::range_value_t<R>>, Allocator>; template<class charT, class traits, class Allocator = allocator<charT>> explicit basic_string(basic_string_view<charT, traits>, const Allocator& = Allocator()) -> basic_string<charT, traits, Allocator>; template<class charT, class traits, class Allocator = allocator<charT>> basic_string(basic_string_view<charT, traits>, typename see below::size_type, typename see below::size_type, const Allocator& = Allocator()) -> basic_string<charT, traits, Allocator>; }
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A size_type parameter type in a basic_string deduction guide refers to the size_type member type of the type deduced by the deduction guide.
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The types iterator and const_iterator meet the constexpr iterator requirements ([iterator.requirements.general]).