problem in c programming

hi, i have this problem: http://pastebin.com/LMm1Sxh8

#pragma once
The above forces the compiler to include the current file just once.

resolved: in b.h i had to write:
struct a;
typedef struct a a_t;

#pragma once , and make sure you define a type/struct before you use it
The headers load from the top to the bottom
#include "first.h"->which starts with #include "second.h"->which starts with #include "third.h"
will load in this order: third.h+second.h+first.h+rest of code

>>1
HAY STACK BOY, HEREZ MY PROGRAM THAT PICKS YOU UP ON A MAGIC CARPET AND SHOVES YOUR HEAD IN YOUR GRANDMA'S ANUS:

int main(void) { int a, b = a + 10; return 0; }

HOW DO YOU LIKE THAT, STACK BOY?

YAINT RED DA FUCKIN STANDARD
YAINT KNO WATS UNDEFINED BEHAVIOUR IF IT POKED YA IN THE ANUS
YAINT CLEVER NUFF TO BE A PROGRAMMER
Y'ONLY GOOD NUFF TO BE ZED SHAW JUNIOR, WHO POKES AND PRODS SHIT WITHOUT EVER READING A FUCKING SPEC.

BACK TO RETOID SKOOL WITH YOU, STACK BOY.

>>5
dude, seriously, fuck you