std::basic_string<CharT,Traits,Allocator>::insert
< cpp | string | basic string
basic_string& insert( size_type index, size_type count, CharT ch ); |
(1) | |
basic_string& insert( size_type index, const CharT* s ); |
(2) | |
basic_string& insert( size_type index, const CharT* s, size_type count ); |
(3) | |
basic_string& insert( size_type index, const basic_string& str ); |
(4) | |
(5) | ||
basic_string& insert( size_type index, const basic_string& str, size_type index_str, size_type count ); |
(until C++14) | |
basic_string& insert( size_type index, const basic_string& str, size_type index_str, size_type count = npos); |
(since C++14) | |
(6) | ||
iterator insert( iterator pos, CharT ch ); |
(until C++11) | |
iterator insert( const_iterator pos, CharT ch ); |
(since C++11) | |
(7) | ||
void insert( iterator pos, size_type count, CharT ch ); |
(until C++11) | |
iterator insert( const_iterator pos, size_type count, CharT ch ); |
(since C++11) | |
(8) | ||
template< class InputIt > void insert( iterator pos, InputIt first, InputIt last ); |
(until C++11) | |
template< class InputIt > iterator insert( const_iterator pos, InputIt first, InputIt last ); |
(since C++11) | |
iterator insert( const_iterator pos, std::initializer_list<CharT> ilist ); |
(9) | (since C++11) |
template < class T > basic_string& insert( size_type pos, const T& t ); |
(10) | (since C++17) |
template < class T > basic_string& insert( size_type index, const T& t, |
(11) | (since C++17) |
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(index_str, 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
. This overload does not participate in overload resolution if InputIt
does not satisfy LegacyInputIterator. (since C++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 pos
, as if by insert(pos, sv.data(), sv.size()). This overload only participates in overload resolution if std::is_convertible_v<const T&, std::basic_string_view<CharT, Traits>> is true and std::is_convertible_v<const T&, 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 pos
, the characters from the subview [index_str, index_str+count)
of sv
. If the requested subview lasts past the end of sv
, or if count == npos, the resulting subview is [index_str, sv.size())
. If index_str > sv.size(), or if index > size(), std::out_of_range is thrown. This overload only participates in overload resolution if std::is_convertible_v<const T&, std::basic_string_view<CharT, Traits>> is true and std::is_convertible_v<const T&, const CharT*> is false.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 |
index_str | - | position of the first character in the string 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 |
Type requirements | ||
-InputIt must meet the requirements of LegacyInputIterator.
|
Return value
1-5,10-11) *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
)Exceptions
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 and may throw any exceptions thrown by Allocator::allocate
.
In any case, if an exception is thrown for any reason, this function has no effect (strong exception guarantee). | (since C++11) |
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
LWG 2946 | C++17 | string_view overload causes ambiguity in some cases
|
avoided by making it a template |
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 index_str, 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); }
See also
appends characters to the end (public member function) | |
appends a character to the end (public member function) |