Programming

 
$ cat practise.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <pthread.h>
#include <semaphore.h>
#include <sys/sem.h>
int count = 0;
int pargc;
char **pargv;
sem_t sem1;
sem_t sem2;
void *thread1(void *);
void *thread2(void *);
int main(int argc, char *argv[])
{
        pargc = argc;
        pargv = argv;
        if(argc != 3)
        {
                printf("Invalid no. of arguments!\n");
                exit(-1);
        }
        else
        {
        sem_init(&sem1,count,1);
        sem_init(&sem2,count,0);
        pthread_t tid1;
        pthread_t tid2;
        int t1 = 1;
        int t2 = 2;
        pthread_attr_t attr1;
        pthread_attr_t attr2;
        pthread_attr_init(&attr1);
        pthread_attr_init(&attr2);
        {
        pthread_create(&tid1,&attr1,thread1,(void *)t1);
        pthread_create(&tid2,&attr2,thread2,(void *)t2);
        }
        {
        pthread_join(tid1,NULL);
        pthread_join(tid2,NULL);
        }
        printf("\nThreads finished!\n");
        }
        return 0;
}
void *thread1(void *n)
{
        int i = 0;
        while(i < 3)
        {
        sem_wait(&sem1);
        count++;
        printf("Count = %d\n",count);
        sem_post(&sem2);
        i++;
        }
        pthread_exit(0);
}
void *thread2(void *n)
{
        int i = 0;
        while(i<3)
        {
        sem_wait(&sem2);
        count--;
        printf("Count = %d\n",count);
        sem_post(&sem1);
        i++;
        }
        pthread_exit(0);
}