std::basic_string<CharT,Traits,Allocator>::operator+=

	(1)
`basic_string& operator+=( const basic_string& str );`			(C++20)
`constexpr basic_string& operator+=( const basic_string& str );`			(C++20)
		(2)
`basic_string& operator+=( CharT ch );`				(C++20)
`constexpr basic_string& operator+=( CharT ch );`				(C++20)
			(3)
`basic_string& operator+=( const CharT* s );`					(C++20)
`constexpr basic_string& operator+=( const CharT* s );`					(C++20)
				(4)
`basic_string& operator+=( std::initializer_list<CharT> ilist );`						(C++11) (C++20)
`constexpr basic_string& operator+=( std::initializer_list<CharT> ilist );`						(C++20)
					(5)
`template < class T > basic_string& operator+=( const T& t );`							(C++17) (C++20)
`template < class T > constexpr basic_string& operator+=( const T& t );`							(C++20)

1) str

2) ch

3) s

4) ilist

5) std::basic_string_view<CharT, Traits> sv = t; t sv append(sv) sv std::is_convertible_v<const T&, std::basic_string_view<CharT, Traits>> true std::is_convertible_v<const T&, const CharT*> false

str	-
ch	-
s	-
ilist	-	std::initializer_list
t	-	(std::basic_string_view )

*this

std::vector::insert

() (C++11)

size() > max_size() std::length_error

(2) CharT CharT char std::string

C++

DR
LWG 2946	C++17	`string_view` overload causes ambiguity in some cases	avoided by making it a template

Run this code

#include <iostream>
#include <iomanip>
#include <string>

int main()
{
   std::string str;
   str.reserve(50); //reserves sufficient storage space to avoid memory reallocation
   std::cout << std::quoted(str) << '\n'; //empty string

   str += "This";
   std::cout << std::quoted(str) << '\n';

   str += std::string(" is ");
   std::cout << std::quoted(str) << '\n';

   str += 'a';
   std::cout << std::quoted(str) << '\n';

   str += {' ','s','t','r','i','n','g','.'};
   std::cout << std::quoted(str) << '\n';

   str += 76.85; // equivalent to str += static_cast<char>(76.85), might not be the intent
   std::cout << std::quoted(str) << '\n';
}

:

""
"This"
"This is "
"This is a"
"This is a string."
"This is a string.L"

append

() [edit]

cppreference.com

std::basic_string<CharT,Traits,Allocator>::operator+=