Compile error from newbie to g++ and Qt

Trying to compile a simple example from a book, I get an error that I don't know what it means. Can anyone give any clues please ?

This is the command line and error message:

g++ -ansi -pedantic -Wall -o test test.cpp
test.cpp: In function ‘int main()’:
test.cpp:7: error: aggregate ‘std::ostringstream strbuf’ has incomplete type and cannot be defined

This is the program:

Code:

---

#include <iostream>
int main()
{
   using namespace std;
   ostringstream strbuf;
   int lucky=7;
   float pi=3.14;
   double e=2.71;
   strbuf << "lucky number " << lucky << endl
   << "pi " << pi << endl
   << "e " << e << endl;
   string strval=strbuf.str();
   cout << strval;
   ofstream outf;
   outf.open("mydata");
   outf << strval;
   outf.close();
   return 0;
}

---

You need to include <sstream> as well.

Thank you.
So I assume "incomplete type and cannot be defined" means "cannot resolve dependencies"
Original error went away, now ofstream has has same problem.
Including <ofstream> said "file not found" and <ostream> made no difference. I thought it would have been standard c/c++ headers ? are the headers documented somewhere ? :confused:

Quote:

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Originally Posted by vieraci

Original error went away, now ofstream has has same problem.
Including <ofstream> said "file not found" and <ostream> made no difference. I thought it would have been standard c/c++ headers ?

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Include <fstream>.

Quote:

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Originally Posted by vieraci

are the headers documented somewhere ? :confused:

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http://www.cplusplus.com/reference/

Quote:

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Originally Posted by vieraci

So I assume "incomplete type and cannot be defined" means "cannot resolve dependencies"

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It means you're referrencing some identifier as a class which hasn't been defined.