/* File: main3.c

   This is a simple main program.
   It's main purpose is to include the header
   files new_header.h and new_header2.h to show how 
   #include and #ifndef work.
*/

#include "new_header.h"
#include "new_header2.h"

main() {
  int n ;

  n = sum(3, 4) ;
  n = diff(5,7) ;
}