I've been programming C++ for too long to really understand why people find pointers hard, but I do remember that I did too at the beginning, and I do remember my epiphany (reading on the train, funny how I remember such senseless details 15 years later yet can't memorize a 4-item shopping list): given a declaration of
struct Foo {
int a;
};
Foo* f;
, the following two are equivalent:
int b = f->a;
and
int b = (*f).a;
Never had it spelled out for me like this, probably because it's so obvious once you get it - thought I'd share in case it gives anyone else an 'aha' moment.
The trick to teaching pointers is to model memory with boxes. You have a stack, and a heap, and you draw arrows to represent pointers. At some point, you need to reveal that those arrows are just numeric indices, but the visual helps early on. The * and & operators just let you follow the value in the pointer. I've had a number of students who were baffled up until I showed them this model.
In general, thinking of memory as an array of bytes is helpful, and each byte has an address which is itself a series of bits that can be stored in memory --- and the concept that ties it all together and what I find makes a lot of people just "get it" is the fact that memory can itself store addresses that denote locations within it.
i also had trouble with pointers while learning C, and, like everyone else, it seems so obvious now that i wonder what the hell my problem was. like learning to ride a bike, or drive a car with a manual transmission. i learned 8086 assembler before C and had no difficulty with indirection there.
for what its worth, your "aha" scenario would have just confused me more. even today, i have to think a bit before your second example makes sense to me.
