Converting ostream into standard string

Question

I am very new to the C++ STL, so this may be trivial. I have a ostream variable with some text in it.

ostream* pout;
(*pout) << "Some Text";

Is there a way to extract the stream and store it in a string of type char*?

score 211 · Answer 1 · edited Apr 24 '14 at 23:12

211

The question was on ostream to string, not ostringstream to string.

For those interested in having the actual question answered (specific to ostream), try this:

void someFunc(std::ostream out)
{
    std::stringstream ss;
    ss << out.rdbuf();
    std::string myString = ss.str();
}

edited Apr 24 '14 at 23:12

Kalin

answered Jul 22 '13 at 21:34

Foo

4

I'll give you points for being a hothead. Alright.. and for the right answer, heh. – moodboom Nov 22 '13 at 18:16
38

This is the correct answer. The answer above, marked as correct, does NOT answer the question. – Matthew James Briggs Jun 19 '14 at 20:48
7

The parameter should be `std::ostream& out` because `std::ostream` isn't copyable. – Brandon Jun 09 '19 at 02:14

score 71 · Accepted Answer · edited May 23 '17 at 12:09

71

     std::ostringstream stream;
     stream << "Some Text";
     std::string str =  stream.str();
     const char* chr = str.c_str();

And I explain what's going on in the answer to this question, which I wrote not an hour ago.

edited May 23 '17 at 12:09

Community

answered Aug 18 '10 at 14:35

James Curran

I get the following error message: 'struct std::basic_ostream >' has no member named 'str' – Stephen Diehl Aug 18 '10 at 14:44
14

Include the necessary headers .`#include ` and `#include ` – Prasoon Saurav Aug 18 '10 at 14:46
18

It's not ostream. It is ostringstream – Vanuan Mar 13 '12 at 14:22
4

Note that ostringstream << int seems to return a basic_ostream but won't change the type of the lhs? Thus having something like `oss << value; return oss.str();` will compile while `return (oss << value).str();` will not. – ArtOfWarfare Jan 25 '13 at 00:53
8

This doesn't answer the question, which was "convert ostream to std:string" – Danny Mar 18 '17 at 06:57
@Danny It answers the question stated in the text of the message, not the (different) question asked in the title. – James Curran Mar 19 '17 at 11:03
10

Weird. From what I see, neither the title nor text of the question contain the word "ostringstream", while your answer does not contain the word "ostream". – Danny Mar 20 '17 at 05:46
1

This doesn't answer the question. It's regarding a `ostream`, not `ostringstream`. – Marc Dirven Jul 15 '21 at 09:23

score 7 · Answer 3 · edited Apr 20 '16 at 08:02

7

   std::ostringstream os;
   os<<"Hello world";
   std::string s=os.str();
   const char *p = s.c_str();

edited Apr 20 '16 at 08:02

Community

answered Aug 18 '10 at 14:37

Prasoon Saurav

1

The question isn't about `std::ostringstream` but about `std::ostream`. `std::ostream` doesn't have a method `.str()`. – Marc Dirven Jul 15 '21 at 09:26

3 Answers3