std::basic_string<CharT,Traits,Allocator>::insert

 

哋它亢++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (哋它亢++20)

Language support library

Concepts library (哋它亢++20)

Metaprogramming library (哋它亢++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (哋它亢++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (哋它亢++17)

Regular expressions library (哋它亢++11)

Concurrency support library (哋它亢++11)

Technical specifications

Symbols index

External libraries

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

basic_string_view (哋它亢++17)

char_traits

 

std::basic_string

Member functions basic_string::basic_string basic_string::~basic_string basic_string::operator= basic_string::assign basic_string::assign_range (哋它亢++23) basic_string::get_allocator Element access basic_string::at basic_string::operator[] basic_string::front (DR*) basic_string::back (DR*) basic_string::data basic_string::c_str basic_string::operator  basic_string_view (哋它亢++17) Iterators basic_string::beginbasic_string::cbegin (哋它亢++11) basic_string::endbasic_string::cend (哋它亢++11) basic_string::rbeginbasic_string::crbegin (哋它亢++11) basic_string::rendbasic_string::crend (哋它亢++11) Capacity basic_string::empty basic_string::sizebasic_string::length basic_string::max_size basic_string::reserve basic_string::capacity basic_string::shrink_to_fit (DR*) Modifiers basic_string::clear basic_string::insert basic_string::insert_range (哋它亢++23) basic_string::erase basic_string::push_back basic_string::pop_back (DR*) basic_string::append basic_string::append_range (哋它亢++23) basic_string::operator+= basic_string::replace basic_string::replace_with_range (哋它亢++23) basic_string::copy basic_string::resize basic_string::resize_and_overwrite (哋它亢++23)   basic_string::swap

Search basic_string::find basic_string::rfind basic_string::find_first_of basic_string::find_first_not_of basic_string::find_last_of basic_string::find_last_not_of Operations basic_string::compare basic_string::starts_with (哋它亢++20) basic_string::ends_with (哋它亢++20) basic_string::contains (哋它亢++23) basic_string::substr Constants basic_string::npos Non-member functions operator+ swap(std::basic_string) erase(std::basic_string)erase_if(std::basic_string) (哋它亢++20)(哋它亢++20) I/O operator<<operator>> getline Comparison operator==operator!=operator<operator>operator<=operator>=operator<=> (until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(哋它亢++20) Numeric conversions stoistolstoll (哋它亢++11)(哋它亢++11)(哋它亢++11) stoulstoull (哋它亢++11)(哋它亢++11) stofstodstold (哋它亢++11)(哋它亢++11)(哋它亢++11) to_string (哋它亢++11) to_wstring (哋它亢++11) Literals operator""s (哋它亢++14) Helper classes hash<std::basic_string> (哋它亢++11) Deduction guides (哋它亢++17)

 

basic_string& insert( size_type index, size_type count, CharT ch );	(1)	(constexpr since 哋它亢++20)
basic_string& insert( size_type index, const CharT* s );	(2)	(constexpr since 哋它亢++20)
basic_string& insert( size_type index, const CharT* s, size_type count );	(3)	(constexpr since 哋它亢++20)
basic_string& insert( size_type index, const basic_string& str );	(4)	(constexpr since 哋它亢++20)
	(5)
basic_string& insert( size_type index, const basic_string& str,                       size_type s_index, size_type count );			(until 哋它亢++14)
basic_string& insert( size_type index, const basic_string& str,                       size_type s_index, size_type count = npos );			(since 哋它亢++14) (constexpr since 哋它亢++20)
		(6)
iterator insert( iterator pos, CharT ch );				(until 哋它亢++11)
iterator insert( const_iterator pos, CharT ch );				(since 哋它亢++11) (constexpr since 哋它亢++20)
			(7)
void insert( iterator pos, size_type count, CharT ch );					(until 哋它亢++11)
iterator insert( const_iterator pos, size_type count, CharT ch );					(since 哋它亢++11) (constexpr since 哋它亢++20)
				(8)
template< class InputIt > void insert( iterator pos, InputIt first, InputIt last );						(until 哋它亢++11)
template< class InputIt > iterator insert( const_iterator pos, InputIt first, InputIt last );						(since 哋它亢++11) (constexpr since 哋它亢++20)
iterator insert( const_iterator pos, std::initializer_list<CharT> ilist );					(9)	(since 哋它亢++11) (constexpr since 哋它亢++20)
template< class StringViewLike > basic_string& insert( size_type index, const StringViewLike& t );					(10)	(since 哋它亢++17) (constexpr since 哋它亢++20)
template< class StringViewLike > basic_string& insert( size_type index, const StringViewLike& t,                       size_type t_index, size_type count = npos );					(11)	(since 哋它亢++17) (constexpr since 哋它亢++20)

Inserts characters into the string.

1) Inserts count copies of character ch at the position index.

2) Inserts null-terminated character string pointed to by s at the position index. The length of the string is determined by the first null character using Traits::length(s).

3) Inserts the characters in the range [s, s + count) at the position index. The range can contain null characters.

4) Inserts string str at the position index.

5) Inserts a string, obtained by str.substr(s_index, count) at the position index.

6) Inserts character ch before the character pointed by pos.

7) Inserts count copies of character ch before the element (if any) pointed by pos.

8) Inserts characters from the range [first, last) before the element (if any) pointed by pos, as if by insert(pos - begin(), basic_string(first, last, get_allocator())).

This overload does not participate in overload resolution if InputIt does not satisfy LegacyInputIterator.

(since 哋它亢++11)

9) Inserts elements from initializer list ilist before the element (if any) pointed by pos.

10) Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then inserts the elements from sv before the element (if any) pointed by index, as if by insert(index, sv.data(), sv.size()).

This overload participates in overload resolution only if std::is_convertible_v<const StringViewLike&,
                      std::basic_string_view<CharT, Traits>> is true and std::is_convertible_v<const StringViewLike&, const CharT*> is false.

11) Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then inserts, before the element (if any) pointed by index, the characters from the subview [t_index, t_index + count) of sv.

• If the requested subview lasts past the end of sv, or if count == npos, the resulting subview is [t_index, sv.size()).
• If t_index > sv.size(), or if index > size(), std::out_of_range is thrown.

This overload participates in overload resolution only if std::is_convertible_v<const StringViewLike&,
                      std::basic_string_view<CharT, Traits>> is true and std::is_convertible_v<const StringViewLike&, const CharT*> is false.

If pos is not a valid iterator on *this, the behavior is undefined.

Parameters

index	-	position at which the content will be inserted
pos	-	iterator before which the characters will be inserted
ch	-	character to insert
count	-	number of characters to insert
s	-	pointer to the character string to insert
str	-	string to insert
first, last	-	range defining characters to insert
s_index	-	position of the first character in str to insert
ilist	-	std::initializer_list to insert the characters from
t	-	object (convertible to std::basic_string_view) to insert the characters from
t_index	-	position of the first character in t to insert
Type requirements
- InputIt must meet the requirements of LegacyInputIterator.

Return value

1-5) *this

6-9) An iterator which refers to the copy of the first inserted character or pos if no characters were inserted (count == 0 or first == last or ilist.size() == 0)

10,11) *this

Exceptions

1-4,10) Throws std::out_of_range if index > size().

5) Throws std::out_of_range if index > size() or if s_index > str.size().

11) Throws std::out_of_range if index > size() or if t_index > sv.size().

In all cases, throws std::length_error if size() + ins_count > max_size() where ins_count is the number of characters that will be inserted.

In all cases, if std::allocator_traits<Allocator>::allocate throws an exception, it is rethrown.

(since 哋它亢++20)

If an exception is thrown for any reason, this function has no effect (strong exception safety guarantee).

Example

Run this code

#include <cassert>
#include <iterator>
#include <string>
 
using namespace std::string_literals;
 
int main()
{
    std::string s = "xmplr";
 
    // insert(size_type index, size_type count, char ch)
    s.insert(0, 1, 'E');
    assert("Exmplr" == s);
 
    // insert(size_type index, const char* s)
    s.insert(2, "e");
    assert("Exemplr" == s);
 
    // insert(size_type index, string const& str)
    s.insert(6, "a"s);
    assert("Exemplar" == s);
 
    // insert(size_type index, string const& str,
    //        size_type s_index, size_type count)
    s.insert(8, " is an example string."s, 0, 14);
    assert("Exemplar is an example" == s);
 
    // insert(const_iterator pos, char ch)
    s.insert(s.cbegin() + s.find_first_of('n') + 1, ':');
    assert("Exemplar is an: example" == s);
 
    // insert(const_iterator pos, size_type count, char ch)
    s.insert(s.cbegin() + s.find_first_of(':') + 1, 2, '=');
    assert("Exemplar is an:== example" == s);
 
    // insert(const_iterator pos, InputIt first, InputIt last)
    {
        std::string seq = " string";
        s.insert(s.begin() + s.find_last_of('e') + 1,
            std::begin(seq), std::end(seq));
        assert("Exemplar is an:== example string" == s);
    }
 
    // insert(const_iterator pos, std::initializer_list<char>)
    s.insert(s.cbegin() + s.find_first_of('g') + 1, {'.'});
    assert("Exemplar is an:== example string." == s);
}

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published 哋它亢++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 7	哋它亢++98	overload (8) referred to a non-existing overload	refers to overload (4) correctly
LWG 847	哋它亢++98	there was no exception safety guarantee	added strong exception safety guarantee
LWG 2946	哋它亢++17	overload (10) caused ambiguity in some cases	avoided by making it a template

See also

insert_range (哋它亢++23)	inserts a range of characters (public member function)
append	appends characters to the end (public member function)
push_back	appends a character to the end (public member function)