#include <stdio.h>
    #include <stdlib.h>
    #include <errno.h>
    #include <sys/types.h>
    #include <sys/ipc.h>
    #include <sys/sem.h>

    int main(void)
    {
        key_t key;
        int semid;
       

        key = ftok("writer.c", 'J');
	semid = semget(key,2,IPC_CREAT | 0600);
	semctl(semid,0,SETVAL,1);
	semctl(semid,1,SETVAL,1);



int i;
for(i = 0; i<5; i++){

semctl(semid,0,SETVAL,0);
semctl(semid,1,SETVAL,0);
printf("Writing\n");
sleep(4);
printf("done\n");
semctl(semid,0,SETVAL,1);
semctl(semid,1,SETVAL,1);
sleep(8);

}


        return 0;
    }