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std::basic_string::operator+=

From cppreference.com
< cpp‎ | string‎ | basic string
 
 
 
std::basic_string
 
basic_string& operator+=( const basic_string& str );
(1)
basic_string& operator+=( CharT ch );
(2)
basic_string& operator+=( const CharT* s );
(3)
basic_string& operator+=( std::initializer_list<CharT> ilist );
(4) (since C++11)

Appends addinional characters to the string.

1) Appends string str

2) Appends character ch

3) Appends the null-terminated character string pointed to by s.

4) Appends characters in the initializer list ilist.

Contents

[edit] Parameters

ch - character value to append
str - string to append
s - pointer to a null-terminated character string to append
init - initializer list with the characters to append

[edit] Return value

*this

[edit] Complexity

1) linear in size of str

2) constant

3) linear in size of s

4) linear in size of init

[edit] Exceptions

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

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

[edit] Example

#include <iostream>
#include <string>
 
int main()
{
   std::string str;
   str.reserve(50); //reserves sufficient storage space to avoid memory reallocation
   std::cout << str << '\n'; //empty string
 
   str += "This";
   std::cout << str << '\n';
 
   str += std::string(" is ");
   std::cout << str << '\n';
 
   str += 'a';
   std::cout << str << '\n';
 
   str += {' ','s','t','r','i','n','g','.'};
   std::cout << str << '\n';
}

Output:

This
This is
This is a
This is a string.

[edit] See also

assign characters to a string
(public member function) [edit]