What does string::npos mean in this code?

Question

What does the phrase std::string::npos mean in the following snippet of code?

found = str.find(str2);

if (found != std::string::npos)
    std::         


        

Answer 1

An answer for these days of C++17, when we have std::optional:

If you squint a bit and pretend std::string::find() returns an std::optional (which it sort of should...) - then the condition becomes:

auto position = str.find(str2);

if ( position.has_value() ) {
    std::cout << "first 'needle' found at: " << found.value() << std::endl;
}