lassie% /lib/cpp -C -P main.c
/* File: main.c

   This is a simple main program.  
   It's main purpose is to include the header
   file header.h to show how #include and #ifndef work.
*/


/**** File: header.h 
   This is a  simple header file.
*/

int sum(int, int) ;
int global_variable = 1 ;

/**** End of file: header.h */

main() {
  int n ;

  n = sum(3, 4) ;
}
lassie%