I've got 2 classes, Store and Transaction and I would like to create a priority queue of objects Transaction as a variable of Store class. I actually already asked similar question couple days ago and you were able to help, but those operators seems to be my Nemesis.
I noticed a possible solution to your problem. I noticed that the priority_queue has a pointer to a transaction, and the operator()(...) takes in a reference. Did you make sure to convert the pointer to a reference?
Of course, this is just guessing from your code, and I don't have any personal experience with std::queue
EDIT: Nevermind. After reading the next one, I've got a feeling my hypothesis was definitely wrong.
If you are trying to overload an operator in your class, the operator parameters can only contain zero or one other object. This is because the left hand side of the operator is substituted as the first argument to the operator and the other object on the left hand side of the operator is used as the second argument.
To fix any errors you have, you can make all the operators in your class friends to the class, that way they can take 2 parameters