Programming

 #include <stdio.h>
#include <semaphore.h>
#include <stdlib.h>
main() {
  sem_t s1;
  sem_t s2;
  int value1 , value2;

  sem_init(&s1, 0, 1);
  sem_init(&s2,0,1);
 
  sem_wait(&s2);
  
  
  int pid = fork();
  
  
  if (pid != 0)
  	{
  		int i;
  		for (i=0 ; i<=10 ; i++)
  		{
  			sem_getvalue (&s1,&value1);
  			while (value1 != 1)
  			  sem_getvalue (&s1,&value1);
  			  
  			sem_wait(&s1);
  			if (i%2 != 0)
  				printf("%d\n",i);
  				
  			sem_post(&s2);
  		}
  	}
  	
  	
  	if (pid == 0)
  	{
  		int j;
  		for (j=0 ; j<=10 ; j++)
  		{
  			sem_getvalue (&s2,&value2);
  			while (value2 != 1)
  			  sem_getvalue (&s2,&value2);
  			  
  			sem_wait(&s2);
  			if (j%2 == 0)
  				printf("%d\n",j);
  				
  			sem_post(&s1);	  
  		}
  		exit(0);
  	}
  
  
  
 return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <time.h>

#define BSZ 20
#define MGC 12

void do_msg_send(int []);

int main(void) {
int err;
int pip[2];
char bbuf[BSZ];
pid_t fng;

                       pipe(pip);
                       if ( (fng = fork()) == 0) {
                                                 do_msg_send(pip);
                       }
                       close(pip[1]);
                       while (1) {
                                 if (read(pip[0],bbuf,BSZ) > 0) {
                                     printf("Received packet from child %d = %s..Announcing availability of data.\n",fng,bbuf);
                                 }
                       }
}

void do_msg_send(int pip[]) {
int rseed;
char nbuf[BSZ];
time_t foo, now;

          
                        close(pip[0]);
                        now = foo = time(NULL);
                        foo += (int)(1 + rand() % MGC);
                        while (1) {
                              now = time(NULL);
                              if (now >= foo) {
                                 sprintf(nbuf,"%d",time(NULL));
                                 write(pip[1],nbuf,BSZ);
                                 foo += (int)(1 + rand() % MGC); 
                              }
                              sleep(1);
                       }
}