Getting error 'No operator "<<" matches these operands' when trying to pass std::string to ostream

Question

I wanted to learn c++, so I attented to a c++ programming course. Mostly it's pretty simple stuff, but now I've ran couple times into this weird situation where I can't use '<<' operands to pass std::string into ostream, even though most of the times I'm able to do so.

As an IDE I am using vs2015 and I have the following code.

#include "stdafx.h"
#include <iostream>

int main() 
{
    std::string str = "Foo";
    std::cout << str << std::endl;
}

What happens is that the '<<' operands between std::cout and str get redlined and I get error message saying: "no operator "<<" matches these operands. Operand types are: std::ostream << std::string".

This happens quite randomly and rarely, so I haven't been able to figure out any type of correlation between the cases. One thing I noticed is that including <sstream> to the project will get rid of the problem, but I don't think thats how it should be.

Any suggestions?

btw IDE diagnostics can be misleading and sometime even wrong. Compiler errors can be verbose and sometimes confusing, but to my experience they much better tell you what is really wrong — 463035818_is_not_an_ai, Oct 16 '17 at 12:11
Thanks, it worked fine after including . It' was confusing because the material (online compiler) provided by school did not need to have included in order for the given code to work. — Lasse Liimatta, Oct 16 '17 at 12:22
@LasseLiimatta Sometimes you do, sometimes you don't. In order to have legal code though you need to include each header you using things from. — NathanOliver, Oct 16 '17 at 12:24

Getting error 'No operator "<<" matches these operands' when trying to pass std::string to ostream

0 Answers0