std::basic_ostringstream<CharT,Traits,Allocator>::str
| (1) | ||
|
(until C++20) | |
|
(since C++20) | |
|
(2) | (since C++20) |
|
(3) | (since C++20) |
|
(4) | |
|
(5) | (since C++20) |
|
(6) | (since C++20) |
|
(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();) results in a dangling pointer.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_sstream_from_string_view |
202306L | (C++26) | Interfacing std::stringstreams with std::string_view, (7) |
Example
#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>) |
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