Compile error from newbie to g++ and Qt

[vieraci]

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:stringstream strbuf’ has incomplete type and cannot be defined

This is the program:

#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;
}

#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;
}

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[wysota]

You need to include <sstream> as well.

[vieraci]

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 ?

[jpn]

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 ?

Include <fstream>.

are the headers documented somewhere ?

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

[wysota]

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

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