std::basic_ostringstream<CharT,Traits,Allocator>::str
From cppreference.com
< cpp | io | basic ostringstream
| (1) | ||
|
std::basic_string
<CharT, Traits, Allocator> str(
)
const
;
|
(until C++20) | |
|
std::basic_string
<CharT, Traits, Allocator> str(
)
const
&
;
|
(since C++20) | |
|
template
<
class SAlloc >
std::basic_string <CharT, Traits, SAlloc> str( const SAlloc& a ) const ; |
(2) | (since C++20) |
|
std::basic_string
<CharT, Traits, Allocator> str(
)
&&
;
|
(3) | (since C++20) |
|
void str(
const
std::basic_string
<CharT, Traits, Allocator>
& s )
;
|
(4) | |
|
template
<
class SAlloc >
void str( const std::basic_string <CharT, Traits, SAlloc> & s ) ; |
(5) | (since C++20) |
|
void str(
std::basic_string
<CharT, Traits, Allocator>
&& s )
;
|
(6) | (since C++20) |
|
template
<
class StringViewLike >
void str( const StringViewLike& t ) ; |
(7) | (since C++26) |
Manages the contents of the underlying string object.
1) Returns a copy of the underlying string. Equivalent to
return rdbuf(
)
-
>str(
)
;
2) Returns a copy of the underlying string, using a as allocator. Equivalent to
return rdbuf(
)
-
>str(a)
;
3) Returns a string move-constructed from the underlying string. Equivalent to
return std::
move
(
*rdbuf(
)
).str
(
)
;
4,5) Replaces the contents of the underlying string. Equivalent to
rdbuf()->str(s);
6) Replaces the contents of the underlying string. Equivalent to
rdbuf(
)
-
>str(std::
move
(s)
)
;
7) Replaces the contents of the underlying string. Equivalent to
rdbuf()->str(t);
This overload participates in overload resolution only if
is_convertible_v<const T&, basic_string_view<charT, traits>>
is true
Parameters
| s | - | new contents of the underlying string |
| t | - | an object (convertible to std::basic_string_view) to use as the new contents of the underlying string |
| a | - | allocator used to construct the returned string |
Return value
1,2) A copy of the underlying string object.
3) A string move-constructed from the underlying string object.
4-7) (none)
Notes
The copy of the underlying string returned by str is a temporary object that will be destructed at the end of the expression, so directly calling c_str() on the result of str() (for example in
auto
*ptr = out.str
(
).c_str
(
)
;
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_sstream_from_string_view |
202306L |
(C++26) | Interfacing std::stringstreams with std::string_view, (7) |
Example
Run this code
#include <iostream> #include <sstream> int main() { int n; std::istringstream in; // could also use in("1 2") in.str("1 2"); in >> n; std::cout << "After reading the first int from \"1 2\", the int is " << n << ", str() = \"" << in.str() << "\"\n"; std::ostringstream out("1 2"); out << 3; std::cout << "After writing the int '3' to output stream \"1 2\"" << ", str() = \"" << out.str() << "\"\n"; std::ostringstream ate("1 2", std::ios_base::ate); ate << 3; std::cout << "After writing the int '3' to append stream \"1 2\"" << ", str() = \"" << ate.str() << "\"\n"; }
Output:
After reading the first int from "1 2", the int is 1, str() = "1 2" After writing the int '3' to output stream "1 2", str() = "3 2" After writing the int '3' to append stream "1 2", str() = "1 23"
See also
| returns the underlying raw string device object (public member function) |
|
| replaces or obtains a copy of the associated character string (public member function of std::basic_stringbuf<CharT,Traits,Allocator>) |