public member function
<string>

std::string::replace

string (1)
string& replace (size_t pos,  size_t len,  const string& str);
string& replace (iterator i1, iterator i2, const string& str);
substring (2)
string& replace (size_t pos,  size_t len,  const string& str,
                 size_t subpos, size_t sublen);
c-string (3)
string& replace (size_t pos,  size_t len,  const char* s);
string& replace (iterator i1, iterator i2, const char* s);
buffer (4)
string& replace (size_t pos,  size_t len,  const char* s, size_t n);
string& replace (iterator i1, iterator i2, const char* s, size_t n);
fill (5)
string& replace (size_t pos,  size_t len,  size_t n, char c);
string& replace (iterator i1, iterator i2, size_t n, char c);
range (6)
template <class InputIterator>
  string& replace (iterator i1, iterator i2,
                   InputIterator first, InputIterator last);
string (1)
string& replace (size_t pos,        size_t len,        const string& str);
string& replace (const_iterator i1, const_iterator i2, const string& str);
substring (2)
string& replace (size_t pos, size_t len, const string& str, size_t subpos, size_t sublen);
c-string (3)
string& replace (size_t pos,        size_t len,        const char* s);
string& replace (const_iterator i1, const_iterator i2, const char* s);
buffer (4)
string& replace (size_t pos,        size_t len,        const char* s, size_t n);
string& replace (const_iterator i1, const_iterator i2, const char* s, size_t n);
fill (5)
string& replace (size_t pos,        size_t len,        size_t n, char c);
string& replace (const_iterator i1, const_iterator i2, size_t n, char c);
range (6)
template <class InputIterator>
  string& replace (const_iterator i1, const_iterator i2,
                   InputIterator first, InputIterator last);
initializer list (7)
string& replace (const_iterator i1, const_iterator i2, initializer_list<char> il);
Replace portion of string
Replaces the portion of the string that begins at character pos and spans len characters (or the part of the string in the range between [i1,i2)) by new contents:

(1) string
Copies str.
(2) substring
Copies the portion of str that begins at the character position subpos and spans sublen characters (or until the end of str, if either str is too short or if sublen is string::npos).
(3) c-string
Copies the null-terminated character sequence (C-string) pointed by s.
(4) buffer
Copies the first n characters from the array of characters pointed by s.
(5) fill
Replaces the portion of the string by n consecutive copies of character c.
(6) range
Copies the sequence of characters in the range [first,last), in the same order.
(7) initializer list
Copies each of the characters in il, in the same order.

Parameters

str
Another string object, whose value is copied.
pos
Position of the first character to be replaced.
If this is greater than the string length, it throws out_of_range.
len
Number of characters to replace (if the string is shorter, as many characters as possible are replaced).
A value of string::npos indicates all characters until the end of the string.
subpos
Position of the first character in str that is copied to the object as replacement.
If this is greater than str's length, it throws out_of_range.
sublen
Length of the substring to be copied (if the string is shorter, as many characters as possible are copied).
A value of string::npos indicates all characters until the end of str.
s
Pointer to an array of characters (such as a c-string).
n
Number of characters to copy.
c
Character value, repeated n times.
first, last
Input iterators to the initial and final positions in a range. The range used is [first,last), which includes all the characters between first and last, including the character pointed by first but not the character pointed by last.
The function template argument InputIterator shall be an input iterator type that points to elements of a type convertible to char.
il
An initializer_list object.
These objects are automatically constructed from initializer list declarators.

size_t is an unsigned integral type.

Return Value

*this

Example

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// replacing in a string
#include <iostream>
#include <string>

int main ()
{
  std::string base="this is a test string.";
  std::string str2="n example";
  std::string str3="sample phrase";
  std::string str4="useful.";

  // replace signatures used in the same order as described above:

  // Using positions:                 0123456789*123456789*12345
  std::string str=base;           // "this is a test string."
  str.replace(9,5,str2);          // "this is an example string." (1)
  str.replace(19,6,str3,7,6);     // "this is an example phrase." (2)
  str.replace(8,10,"just a");     // "this is just a phrase."     (3)
  str.replace(8,6,"a shorty",7);  // "this is a short phrase."    (4)
  str.replace(22,1,3,'!');        // "this is a short phrase!!!"  (5)

  // Using iterators:                                               0123456789*123456789*
  str.replace(str.begin(),str.end()-3,str3);                    // "sample phrase!!!"      (1)
  str.replace(str.begin(),str.begin()+6,"replace");             // "replace phrase!!!"     (3)
  str.replace(str.begin()+8,str.begin()+14,"is coolness",7);    // "replace is cool!!!"    (4)
  str.replace(str.begin()+12,str.end()-4,4,'o');                // "replace is cooool!!!"  (5)
  str.replace(str.begin()+11,str.end(),str4.begin(),str4.end());// "replace is useful."    (6)
  std::cout << str << '\n';
  return 0;
}


Output:
replace is useful.

Complexity

Unspecified, but generally up to linear in the new string length.

Iterator validity

Any iterators, pointers and references related to this object may be invalidated.

Data races

The object is modified.

Exception safety

Strong guarantee: if an exception is thrown, there are no changes in the string.

If s does not point to an array long enough, or if the range specified by [first,last) is not valid, it causes undefined behavior.

If pos is greater than the string length, or if subpos is greater than str's length, an out_of_range exception is thrown.
If the resulting string length would exceed the max_size, a length_error exception is thrown.
A bad_alloc exception is thrown if the function needs to allocate storage and fails.

See also