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

char* delete_tabs(char* new_str,char* text) {
    int j = 0;
    for (int i = 0; i<strlen(text); ++i) {
        if (text[i]=='\t') {
            for (int k = 0; k<3; ++k) {
                new_str[j]=' ';
                ++j;
            }
        } else {
            new_str[j]=text[i];
            ++j;
        }
    }
           printf("%s\n",new_str);

    return new_str;
}

int main()
{

    int fd1[2];
    int fd2[2];
    char result_str[100];
    char input_str[100];
    pid_t p;

    if (pipe(fd1)==-1)
    {
        fprintf(stderr, "Pipe Failed" );
        return 1;
    }
    if (pipe(fd2)==-1)
    {
        fprintf(stderr, "Pipe Failed" );
        return 1;
    }

    p = fork();

    if (p < 0)
    {
        fprintf(stderr, "fork Failed" );
        return 1;
    }

    // Parent process
    else if (p > 0)
    {
        scanf ("%[^\n]%*c", input_str);

        close(fd1[0]);  // Close reading end of first pipe

        // Write input string and close writing end of first
        // pipe.
        write(fd1[1], input_str, strlen(input_str)+1);
        close(fd1[1]);

        // Wait for child to send a string
        wait(NULL);

        close(fd2[1]); // Close writing end of second pipe

        // Read string from child, print it and close
        // reading end.
        read(fd2[0], result_str, 100);
        printf("%s\n",result_str);
        close(fd2[0]);
    }

    // child process
    else
    {
        close(fd1[1]);  // Close writing end of first pipe

        // Read a string using first pipe
        char get_str[100];
        read(fd1[0], get_str, 100);
       char* new_str;
        delete_tabs(new_str,get_str);

       for (int i = 0; i<strlen(new_str); ++i) {
           if (new_str[i]==' ') {
               new_str[i]='_';
           }
       }
        // Concatenate a fixed string with it


        // Close both reading ends
        close(fd1[0]);
        close(fd2[0]);

        // Write concatenated string and close writing end
        write(fd2[1], new_str, strlen(new_str)+1);
        close(fd2[1]);

        exit(0);
    }
    return 0;
}