#include <sys/wait.h>
#include <zconf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>



#define CHILD_AMOUNT 2



int create_child() {
    int i;
    for(i=0;i<CHILD_AMOUNT;i++){
		pid_t pid = fork();
		if (pid== 0) {
			return i+1;
		} else if (pid > 0) {
			continue;
		} else {
			printf("Erro ao fazer fork\n");
			exit(-1);
		}
	}
    return 0;
}

void close_descriptor(int descriptor) {
    if (close(descriptor) == -1) {
        printf("Nao foi possivel fechar o pipe %d\n", descriptor);
        exit(-1);
    }
}


int main(int argc) {
    int fd1[2],fd2[2],id;

	if (pipe(fd1) == -1) {
		printf("Erro ao criar o pipe\n");
		exit(-1);
	}
	if (pipe(fd2) == -1) {
		printf("Erro ao criar o pipe\n");
		exit(-1);
	}

	id=create_child();

	if(id==0){
		close_descriptor(fd1[0]);
		dup2(fd1[1],1);
		execlp("ls","ls","-la",(char*)NULL);
		exit(-1);
	}else if(id==1){
		close_descriptor(fd1[1]);
		close_descriptor(fd2[0]);
		dup2(fd1[0],0);
		dup2(fd2[1],1);
		sleep(1);
		execlp("sort","sort",(char*)NULL);
		exit(-1);
	}else{
		close_descriptor(fd2[1]);
		dup2(fd2[0],0);
		sleep(2);
		execlp("wc","wc","-l",(char*)NULL);
		exit(-1);
	}
}