A few pointers on writing in C.

for-loops.c

/*
*   In C, you cannot do the following:
*   for(int i = 0; i < 5; i++){
*     // do stuff
*   }
*
*   You must do the following:
*/

void main( void ){
  int i;
  for(i = 0; i < 5; i++){
      // do something 5 times!
  }
}

functions.c

/*
*   If you use a function 'b' in function 'a', you *must* either have 'b' ahead of 'a' in your code or do the following:
*/

void b(int);

void main( void ){
  b();
  // do stuff yo
}

void b ( int x ){
  // woah you do some stuff here too!
}

pointers.c

/*
*   Here's a pointer on pointers :)
*/

#define LATCH_ADDR  0x4000
void main( void ){
  // let's write 0x22 to our latch!
  unsigned int* latch = (unsigned int*) LATCH_ADDR;
  *latch = 0x22;
}