#include <stdio.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<signal.h>
#include<unistd.h>
#include<stdlib.h>
#include<assert.h>
#include<string.h>
#include<errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
int main(int argc , char **argv)
{
int fd[2] , n ;
char c ;
pid_t childpid ;
pipe(fd);
#if 1
if((childpid = fork()) == 0)
{
if((n = read(fd[0],&c ,1))!= 1)
perror("no data\n");
printf("child %c %d %d \n",c ,fd[0],fd[1]);
write(fd[1],"c",1);
exit(0);
}
#endif
write(fd[1],"p",1);//31
if((n = read(fd[0],&c ,1))!= 1)
perror("no data\n");
printf("parent %c %d %d \n",c,fd[0],fd[1]);
sleep(6);//35
exit(0);
}