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# std::basic_string::replace

From cppreference.com
< cpp‎ | string‎ | basic string

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

Replaces the part of the string indicated by either `[pos, pos + count)` or `[first, last)` with a new string.

The new string can be one of:

1) string `str`;
2) substring `[pos2, pos2 + count2)` of `str`, except if count2==npos or if would extend past str.size(), `[pos2, str.size())` is used.
3) characters in the range `[first2, last2)`. This overload has the same effect as overload (6) if `InputIt` is an integral type.
4) first `count2` characters of the character string pointed to by `cstr`;
5) null-terminated character string pointed to by `cstr`;
6) `count2` copies of character `ch`;
7) characters in the initializer list `ilist`;
8) characters in the string view `sv` (equivalent to replace(pos, count, sv.data(), sv.size()))
9) characters in the string view `sv` (equivalent to replace(first - begin(), last - first, sv))
10) subview `[pos2, pos2 + count2)` of a string view `sv`, converted from `t` as if by std::basic_string_view<CharT, Traits> sv = t;, except if count2==npos or if it would extend past sv.size(), `[pos2, sv.size())` is used. 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.

### [edit] 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
sv | - | std::basic_string_view with the characters to use for replacement
t | - | object (convertible to std::basic_string_view) with the characters to use for replacement

### [edit] Return value

*this

### [edit] Exceptions

std::out_of_range if `pos > length()` or `pos2 > str.length()`

std::length_error if the resulting string will exceed maximum possible string length (`std::string::npos - 1`)

In any case, if an exception is thrown for any reason, this function has no effect (strong exception guarantee). (since C++11)

### [edit] Example

Run this code

    #include <iostream>
    #include <string>

    int main()
    {
        std::string str("The quick brown fox jumps over the lazy dog.");

        str.replace(10, 5, "red"); // (5)

        str.replace(str.begin(), str.begin() + 3, 1, 'A'); // (6)

        std::cout << str << '\n';
    }

Output:

    A quick red fox jumps over the lazy dog.

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