/* program on  pipe */

# include <stdio.h>
# include <sys/types.h>
# include <stdlib.h>
# define MAXLINE 4096

int main()
{
int n,fd[2];
pid_t pid;
char line[MAXLINE];

if(pipe(fd)<0)
perror("pipe error..");

    if((pid=fork())<0)
    perror("fork error...");
    else
        if(pid>0)
        {
        close(fd[0]);
        write(fd[1],"hello world\n",12);
        }
        else
        {
        close(fd[1]);
        n=read(fd[0],line,MAXLINE);
        write(1,line,n);
        }
exit(0);
}