basic_string&
append(const basic_string& str);
basic_string&
append(const basic_string& str, size_type pos, size_type n = npos);
Effects: Determines the effective length rlen of the string to append as the smaller of n and str.size() - pos and calls append(str.data() + pos, rlen).
basic_string& append(basic_string_view<charT, traits> sv);
template<class T>
basic_string& append(const T& t, size_type pos, size_type n = npos);
Effects: Creates a variable, sv, as if by basic_string_view<charT, traits> sv = t. Determines the effective length rlen of the string to append as the smaller of n and sv.size() - pos and calls append(sv.data() + pos, rlen).
Remarks: This function shall not participate in overload resolution unless is_convertible_v<const T&, basic_string_view<charT, traits>> is true and is_convertible_v<const T&, const charT*> is false.
basic_string&
append(const charT* s, size_type n);
Effects: The function replaces the string controlled by *this with a string of length size() + n whose first size() elements are a copy of the original string controlled by *this and whose remaining elements are a copy of the initial n elements of s.
basic_string& append(const charT* s);
basic_string& append(size_type n, charT c);
template<class InputIterator>
basic_string& append(InputIterator first, InputIterator last);
basic_string& append(initializer_list<charT> il);
void push_back(charT c);