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

size_t is an unsigned variable, thus 'unsigned value = - 1' automatically makes it the largest possible value for size_t: 18446744073709551615