Std::basic_stringstream (3) Linux Manual Page

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

Synopsis

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"

std::basic_stringstream (3) Linux Manual Page