simple C++ hash_set example

Question

I am new to C++ and STL. I am stuck with the following simple example of a hash set storing custom data structures:

#include 
#include 

        

Answer 1

So close! The last error in your output reveals your hash_trip routine should be declared const:

size_t operator()(const trip t) const // note the ending 'const'
{
    //...
}

You'll probably need to do the same thing for eq_trip. Also, I would recommend passing the arguments to these functions by constant reference to avoid an unnecessary copy of the data you're passing:

size_t operator()(const trip& t) const // note the '&'
{
    //...
}