General Information about main.cpp

This will be constantly updated throughout the course of this project. Is it appropriate to
implement Global variables for items, or should I initialize all item objects within the scope of 
main and send them to functions when needed? I ask this because I plan to create a function that
will output the storage value for all player owned items with a storage value greater than 0, and
I am wondering, how I would pass every in-game item to a function without initializing them
globally.