std::basic_string::assign

(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 basic_string::npos).

(3) c-string

Copies the null-terminated character sequence (C-string) pointed by s.
The length is determined by calling traits_type::length(s).

(4) buffer

Copies the first n characters from the array of characters pointed by s.

(5) fill

Replaces the current value 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.

(8) move

Acquires the contents of str.
str is left in an unspecified but valid state.

Parameters

str

Another basic_string object of the same type (with the same class template arguments charT, traits and Alloc), whose value is either copied or moved.

subpos

Position of the first character in str that is copied to the object as a substring.
If this is greater than str's length, it throws out_of_range.
Note: The first character in str is denoted by a value of 0 (not 1).

sublen

Length of the substring to be copied (if the string is shorter, as many characters as possible are copied).
A value of basic_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 charT.
If InputIterator is an integral type, the arguments are casted to the proper types so that signature (5) is used instead.

il

An initializer_list object.
These objects are automatically constructed from initializer list declarators.

Return Value

Example

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// string::assign
#include <iostream>
#include <string>

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

  // used in the same order as described above:

  str.assign(base);
  std::cout << str << '\n';

  str.assign(base,10,9);
  std::cout << str << '\n';         // "brown fox"

  str.assign("pangrams are cool",7);
  std::cout << str << '\n';         // "pangram"

  str.assign("c-string");
  std::cout << str << '\n';         // "c-string"

  str.assign(10,'*');
  std::cout << str << '\n';         // "**********"

  str.assign<int>(10,0x2D);
  std::cout << str << '\n';         // "----------"

  str.assign(base.begin()+16,base.end()-12);
  std::cout << str << '\n';         // "fox jumps over"

  return 0;
}

The quick brown fox jumps over a lazy dog.
brown fox
pangram
c-string
**********
----------
fox jumps over

Complexity

Iterator validity

Data races

Exception safety

See also

basic_string::operator=

String assignment (public member function)

basic_string::append

Append to string (public member function)

basic_string::insert

Insert into string (public member function)

basic_string::replace

Replace portion of string (public member function)