1 #include<stdio.h>
2 #include<unistd.h>
3 #include<stdlib.h>
4
5 int main()
6 {
7     int n;
8     pid_t pid;
9     int fd[2];
10     char line[56];
11     if(pipe(fd) < 0)
12     {
13         printf("pipe error\n");
14     }
15     if((pid = fork()) > 0){
16         close(fd[1]);
17         n = read(fd[0],line,56);
18         if(n > 0){
19             printf("%s\n",line);
20         }
21     }else if(pid == 0){
22         dup2(fd[1],1);
23         close(fd[1]);
24         close(fd[0]);
25         int x = 20;
26         while(x){
27             printf("hello world\n");
28             x--;
29             sleep(1);
30         }
31         return 0;
32     }
33     return 0;
34 }
35