std::basic_ostringstream<CharT,Traits,Allocator>::str (3) - Linux Manuals

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

NAME

std::basic_ostringstream<CharT,Traits,Allocator>::str - std::basic_ostringstream<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"