C - when to use pointer arithmetic, when to use array indexing?

Question

In C, when is it preferrable to use one over the other?

Answer 1

It usually depends on the situation. I don't think there's a rule of thumb.

In some cases, array indexes are better. For example when you have allocated an array

char* ptr = malloc(SIZE);

and you need the value of ptr to not change, because you want to free it later, then you can work with indexes.

Or if you get a pointer as a function argument

void func(char* ptr)

and you need to run over the array, then you can increment the pointer itself and you won't need to create a new variable to use as an index.

In most cases however, it depends on your own preferences.