Question

Hey guys I’m having trouble with some code I’m writing for a .obj model parser.
Here’s the code that’s causing the problem:

std::istringstream iss(line.substr(1));

std::copy(   
std::istream_iterator<float>(iss),     
std::istream_iterator<float>(),    
std::back_inserter<std::vector<float>>(model.chunks.back().vectices)  
);

It’s basically taking a string passed as a argument like this:

v -5.000000 -1.000000 1.000000

Then gets the substring from it so it’s left with only this:

-5.000000 -1.000000 1.000000

Finally I use std::copy and get each set of numbers from within the string:

vertices[0] = -5.000000
vertices[1] = -1.000000
vertices[2] = 1.000000

Anyways the main problem here is that I’m getting an error from this line of code:

std::back_inserter<std::vector<float>>(model.chunks.back().vectices));

It says “expected token ‘;’ got float” my code still compiles and run’s flawlessly though.

Although if I replace the floats in that code with std::string’s I don’t get the error anymore.

std::copy(  
std::istream_iterator<std::string>(iss),   
std::istream_iterator<std::string>(),   
std::back_inserter<std::vector<std::string>>(model.chunks.back().vectices)  
);

I’m using Qt Creator so could this possibly be just a IDE error? Any help would be greatly appreciated!

Answer 1

It might be that your IDE doesn’t understand the >> in your template specification. Older versions of the C++ standard required that you put a space in between each > as in > >, otherwise it could be confused with the right shift operator >>. So:

std::back_inserter<std::vector<float> >(model.chunks.back().vectices));