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

basic_string& replace( size_type pos, size_type count,
                       const basic_string& str );
 (1) (constexpr since C++20) 
basic_string& replace( const_iterator first, const_iterator last,
                       const basic_string& str );
 (2) (constexpr since C++20)
(3) 
basic_string& replace( size_type pos, size_type count,
                       const basic_string& str,
                       size_type pos2, size_type count2 );
 (until C++14) 
basic_string& replace( size_type pos, size_type count,
                       const basic_string& str,
                       size_type pos2, size_type count2 = npos );
 (since C++14)
(constexpr since C++20)		 
basic_string& replace( size_type pos, size_type count,
                       const CharT* cstr, size_type count2 );
 (4) (constexpr since C++20) 
basic_string& replace( const_iterator first, const_iterator last,
                       const CharT* cstr, size_type count2 );
 (5) (constexpr since C++20) 
basic_string& replace( size_type pos, size_type count,
                       const CharT* cstr );
 (6) (constexpr since C++20) 
basic_string& replace( const_iterator first, const_iterator last,
                       const CharT* cstr );
 (7) (constexpr since C++20) 
basic_string& replace( size_type pos, size_type count,
                       size_type count2, CharT ch );
 (8) (constexpr since C++20) 
basic_string& replace( const_iterator first, const_iterator last,
                       size_type count2, CharT ch );
 (9) (constexpr since C++20) 
template< class InputIt >
basic_string& replace( const_iterator first, const_iterator last,
                       InputIt first2, InputIt last2 );
 (10) (constexpr since C++20) 
basic_string& replace( const_iterator first, const_iterator last,
                       std::initializer_list<CharT> ilist );
 (11) (since C++11)
(constexpr since C++20)		 
template< class StringViewLike >
basic_string& replace( size_type pos, size_type count,
                       const StringViewLike& t );
 (12) (since C++17)
(constexpr since C++20)		 
template< class StringViewLike >
basic_string& replace( const_iterator first, const_iterator last,
                       const StringViewLike& t );
 (13) (since C++17)
(constexpr since C++20)		 
template< class StringViewLike >
basic_string& replace( size_type pos, size_type count,
                       const StringViewLike& t,
                       size_type pos2, size_type count2 = npos );
 (14) (since C++17)
(constexpr since C++20)

Replaces the characters in the range [begin() + pos, begin() + std::min(pos + count, size())) or [first, last) with given characters.

1,2) Those characters are replaced with str.
3) Those characters are replaced with a substring [pos2, std::min(pos2 + count2, str.size())) of str.
4,5) Those characters are replaced with the characters in the range [cstr, cstr + count2).
If [cstr, cstr + count2) is not a valid range, the behavior is undefined.
6,7) Those characters are replaced with the characters in the range [cstr, cstr + Traits::length(cstr)).
8,9) Those characters are replaced with count2 copies of ch.
10) Those characters are replaced with the characters in the range [first2, last2) as if by replace(first, last, basic_string(first2, last2, get_allocator())).
11) Those characters are replaced with the characters in ilist.
12,13) Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then those characters are replaced with the characters from sv.
These overloads participate 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.
14) Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then those characters are replaced with the characters from the subview sv.substr(pos2, count2).
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 [begin(), first) or [first, last) is not a valid range, the behavior is undefined.

Parameters

pos - start of the substring that is going to be replaced
count - length of the substring that is going to be replaced
first, last - range of characters that is going to be replaced
str - string to use for replacement
pos2 - start of the substring to replace with
count2 - number of characters to replace with
cstr - pointer to the character string to use for replacement
ch - character value to use for replacement
first2, last2 - range of characters to use for replacement
ilist - initializer list with the characters to use for replacement
t - object (convertible to std::basic_string_view) with the characters to use for replacement
Type requirements
-InputIt must meet the requirements of LegacyInputIterator.

Return value

*this.

Exceptions

1) Throws std::out_of_range if pos > size().
3) Throws std::out_of_range if pos > size() or pos2 > str.size().
4,6,8) Throws std::out_of_range if pos > size().
12,14) Throws std::out_of_range if pos > size().

If the operation would result in size() > max_size(), throws std::length_error.

If an exception is thrown for any reason, these functions have no effect (strong exception safety guarantee).

Example

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 847 C++98 there was no exception safety guarantee added strong exception safety guarantee
LWG 1323 C++98 the types of first and last were iterator changed to const_iterator
LWG 2946 C++17 overloads (12,13) caused ambiguity in some cases avoided by making them templates

See also

(C++23)
replaces specified portion of a string with a range of characters
(public member function)
(C++11)
replaces occurrences of a regular expression with formatted replacement text
(function template)
replaces all values satisfying specific criteria with another value
(function template)

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