Integers are the simple case, but you really haven't grasped the C memory model until you're comfortable handling text strings at any length, calling functions

Integers are the simple case, but you really haven't grasped the C memory model until you're comfortable handling text strings at any length, calling functions by pointers, working with structure pointers, and knowing when you need a pointer to a pointer. Part of it is understanding variable scope, local vs global vs stack frame memory. It's not rocket science, just takes practice, and the courage to segfault your way through it.