What is the difference between -> and dot

Question

In a C program, when i define a struct.

under which circumstances would i use "->" and under which "." ?

for example

typedef struct foo foo;

struct foo{

  double bar;
  double bar2;
}

foo barbar;

when would I use barbar.bar and when would i use barbar->bar ?

This is a much-too-basic C question. Please consult your local C reference book. — Daniel Kamil Kozar, May 09 '14 at 16:02
`->` for pointers, `.` for instances. Also, as Daniel pointed out, basic C pointer question. Should be found in any good book or tutorial. — AntonH, May 09 '14 at 16:02
possible duplicate of [Arrow operator (->) usage in C](http://stackoverflow.com/questions/2575048/arrow-operator-usage-in-c) — Paul R, May 09 '14 at 16:03
duplicate of http://stackoverflow.com/questions/1238613/what-is-the-difference-between-the-dot-operator-and-in-c — phuclv, May 09 '14 at 16:07
`a->b` is *exactly the same* as `(*a).b`, so the answer is: you would use `->` any time you would use `(*a).b`. If you don't understand what `*a` means then you need to go back a step and learn about the fundamental relationships between *storage* and *pointers*. `&` turns *storage* into a *pointer*, and `*` turns a *pointer* back into *storage*. Make sure you understand this at a deep level before you continue. — Eric Lippert, May 09 '14 at 16:14

score 2 · Accepted Answer · answered May 09 '14 at 16:03

2

Left of -> should be pointer type, while normal variables/instances for ..

answered May 09 '14 at 16:03

herohuyongtao

score 1 · Answer 2 · answered May 09 '14 at 16:03

1

Use a -> for a pointer to a struct as it dereferences the pointer, use a . for a struct

answered May 09 '14 at 16:03

jayjay

2 Answers2