fork와 pipe를 사용해서 순환하는 작업

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
 
 
#define FORWARD 1
#define REVERSE 0
 
 
int main(void){
	char buffer[BUFSIZ];
	int fd[5][2][2];
	int read_status = 0;
 
	//파이프 생성.
	//i,0 -> i번째에서 i+1번째에게 받는거, i,1 -> i번째에서 i+1번째에게 보내는거
	for (int i=0;i<5;i++){
    	for(int j=0;j<2;j++){
		if(pipe(fd[i][j])==-1){
        		perror("pipe error..\n");
        		exit(0);
		}
	}
	}
 
	int pid;
	int len;
	int test1;
	int my_pid;
	int fpos;
	my_pid = getpid();
	for(int i=0;i<5;i++){
		if(getpid() != my_pid){
			exit(0);
		}
    		pid = fork();
 
	    	if(pid == -1){
		        perror("fork error..\n");
		        exit(0);
		}
		else if(pid==0){ //자식 프로세스의 경우//
			pid = getpid();
			printf("Child process %d created.\n", pid);
			/*
			if(read(fd[1][FORWARD][0], buffer, BUFSIZ)>0){
				printf("\tComplete %s\n", buffer);
			}
			*/
			if(i==0){
				write(fd[1][FORWARD][1], "Hi. I'm First!", BUFSIZ);
				printf("Write Complete!\n");
			}
			else if(i==1){
				read(fd[1][FORWARD][0], buffer, BUFSIZ);
				printf("Output of child process(%d) :: %s \n",pid ,buffer);
				write(fd[2][FORWARD][1], "Hi. I'm Second!", BUFSIZ);
			}
			else if(i==2){
				read(fd[2][FORWARD][0], buffer, BUFSIZ);
				printf("Output of child process(%d) :: %s \n",pid ,buffer);
				write(fd[3][FORWARD][1], "Hi. I'm Third!", BUFSIZ);
			}
			else if(i==3){
				read(fd[3][FORWARD][0], buffer, BUFSIZ);
				printf("Output of child process(%d) :: %s \n",pid ,buffer);
				write(fd[4][FORWARD][1], "Hi. I'm Forth!", BUFSIZ);
			}
 
		}
		else{ //부모 프로세스의 경우//
			pid = getpid();
			if(i==4){
				read(fd[4][FORWARD][0], buffer, BUFSIZ);
				printf("Output of parent process(%d) :: %s \n",pid ,buffer);
				write(fd[0][FORWARD][1], "Hi. I'm Forth!", BUFSIZ);
			}
		}
 
		sleep(1);
	}
	exit(0);
}