How to read a word from std::istringstream without assigning to a tmp variable through >>?

Question

I have a std::string line which contains a line of text read from a file. I then create a istringstream:

std::istringstream str(line);

to read this line. To get the first word, I do this:

std::string word;
str >> word;

Is there a way to get the word directly from str, without declaring the intermediate variable word?

For example, I would like to do something like:

if (str.get_next_word_directly() == "yes")
     do_something();

Answer 1

You have to use a named variable to do this; it is possible to extract into a temporary but then you have no way of identifying that temporary to call operator== on it.

One option would be to wrap the extraction in a function, e.g.

std::string get_word(std::istream& is)
{
    std::string word;
    is >> word;
    return word;
}

and then you can write

if( get_word(str) == "yes" )

NB. There is a proposal for C++17 that would allow str.get_word() instead of get_word(str); but for now you're stuck with get_word(str).