std::basic_stringstream<CharT,Traits,Allocator>::str

 

C++

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Language support library

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Technical Specifications

 

Input/output library

I/O manipulators

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

strstreambuf (deprecated in C++98)

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ios_base

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basic_istringstream

basic_ostringstream

basic_stringstream

Array I/O

istrstream (deprecated in C++98)

ostrstream (deprecated in C++98)

strstream (deprecated in C++98)

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basic_osyncstream (C++20)

Types

streamoff

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iostream_category (C++11)

io_errc (C++11)

 

std::basic_stringstream

Member functions

basic_stringstream::basic_stringstream

basic_stringstream::operator=

basic_stringstream::swap

basic_stringstream::rdbuf

String operations

basic_stringstream::str

 

std::basic_string<CharT,Traits,Allocator> str() const;	(1)
void str(const std::basic_string<CharT,Traits,Allocator>& new_str);	(2)

Manages the contents of the underlying string object.

1) Returns a copy of the underlying string as if by calling rdbuf()->str().

2) Replaces the contents of the underlying string as if by calling rdbuf()->str(new_str).

Parameters

new_str

-

new contents of the underlying string

Return value

1) a copy of the underlying string object.

2) (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.

Example

Run this code

#include <sstream>
#include <iostream>
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

str	replaces or obtains a copy of the associated character string (public member function of std::basic_stringbuf<CharT,Traits,Allocator>)