aggregate 'std::stringstream out' has incomplete type and cannot be defined [C++]

Question

I am new to c++ please help me figure out what is wrong with this

string c;
stringstream out; //aggregate 'std::stringstream out' has incomplete type and cannot be //defined
out << it->second;
out << end1;//'end1' was not declared in this scope
c = out.str();

Alnitak · Answer 1 · 2011-04-21T21:05:42.017

Did you:

#include <sstream>

Also, the second to last line should be endl (nb: lower-case L) not end1 (number one).

The code below compiles and works correctly with G++ 4.2.1 on MacOS X

#include <iostream>
#include <sstream>

int main() {
        std::stringstream out;
        out << "foo" << std::endl;
        std::string c = out.str();
        std::cout << c;
}

Omitting the #include <sstream> causes exactly the same error on my system as your first error.

karlphillip · Answer 2 · 2011-04-21T20:59:07.653

5

It's an lowercase L and not 1:

out << endl;

I think @Bo is right, (sorry and thanks) change it to std::stringstream out;

edited Apr 21 '11 at 20:59

answered Apr 21 '11 at 20:49

karlphillip

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1

that was the second error thanks, what about the stringstream? – Technupe Apr 21 '11 at 20:50
1

`stringstream` is the superclass and you can't use it directly. Use `istringstream` or `ostringstream` instead. – karlphillip Apr 21 '11 at 20:53
4

`stringstream` is perfectly fine to use, you just have to call it `std::stringstream`. – Bo Persson Apr 21 '11 at 20:57
he's clearly got the namespace imported or the error would have been different. – Alnitak Apr 21 '11 at 20:59
4

I don't think he needs std::stringstream. Rather, I think he's missing the header . – Andrew Rasmussen Apr 21 '11 at 21:17
That tip was in my original answer but I removed it since the OP complaint the error was still happenning. – karlphillip Apr 21 '11 at 21:34

score 3 · Accepted Answer · answered Apr 21 '11 at 20:48

3

You seem to be missing an include for stringstream. On top of that you have a typo

out << end1;

should read

out << endl;

l instead of 1.

answered Apr 21 '11 at 20:48

nathan

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i dont see a difference sorry – Technupe Apr 21 '11 at 20:49
I updated my answer to make it clearer. Font makes it difficult to see the difference, but there is one. – nathan Apr 21 '11 at 20:51

aggregate 'std::stringstream out' has incomplete type and cannot be defined [C++]

3 Answers3