#include "libuser.h"

void Main( int argc , char ** argv )
{

  int i,j ;     	/* loop index */
  int scr_sem; 		/* id of screen semaphore */
  int time; 		/* current and start time */
  int ping,pong;	/* id of semaphores to sync processes b & c */

  time = Get_Time_Of_Day();
  scr_sem = Create_Semaphore ( "screen" , 1 ) ;   /* register for screen use */
  ping = Create_Semaphore ( "ping" , 1 ) ;   
  pong = Create_Semaphore ( "pong" , 0 ) ;  

  for (i=0; i < 5; i++) {
       P(pong);
       for (j=0; j < 35; j++);
       V(ping);
  }

  time = Get_Time_Of_Day() - time;
  P ( scr_sem ) ;
  Print ("Process Ping is done at time: %d\n", time) ;
  V( scr_sem );
  return ( 0 );

}