Structures
Stack principle
w NOTE: Each of the big blocks is a struct (or class) that has a pointer to another one. Remember that the pointer only stores the memory location of something, it is not that thing, so the arrow goes to the next one. At the end, there is nothing for the pointer to point to, so it does not point to anything, it should be set to "NULL" to prevent it from accidentally pointing to a totally arbitrary and random location in memory (which is very bad).

| Think of it like a train. The programmer always stores the first node of the list. This would be the engine of the train. The pointer is the connector between coaches of the train. Every time the train ads a car, it uses the connectors to add a new car. This is like a programmer using the keyword new to create a pointer to a new struct or class.