#include <stdio.h>
#include <error.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>

int main(void){
    int fdsPC[2];  //Parent -> Child
    int fdsCP[2];  //Child -> Parent
    if(pipe(fdsPC) < 0){
        error(errno,errno,NULL);
    }
    
    if(pipe(fdsCP) < 0){
        error(errno,errno,NULL);
    }
    
    pid_t pid= fork();
    if(pid < 0){
        error(errno,errno,NULL);
    } else if (pid == 0){
        close(fdsPC[1]);
        close(fdsCP[0]);
        //I am the child
        char buffer[100] = {0};
        read(fdsPC[0],buffer,99);       
        printf("%s\n",buffer);
        close(fdsPC[0]);
        write(fdsCP[1],"Hello dad",strlen("Hello dad"));
        close(fdsCP[1]);
       
    } else {
        close(fdsPC[0]);
        close(fdsCP[1]);
        write(fdsPC[1],"Hello Child",strlen("Hello Child"));
        close(fdsPC[1]);
        char buffer[100] = {0};
        read(fdsCP[0],buffer,99);
        printf("%s\n",buffer);
        close(fdsCP[0]);  
    }

    return 0;
}