[C] JiMP 10.4

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct book
{
    char authorName[128];
    char title[128];
    int catalogNumber;
    int price;
    struct book *next;
};

void clear()
{
    //printf("\033[H\033[2J");
    system( "cls" );
}

void loadBook(struct book *x)
{
    clear();
    printf("Podaj autora: ");
    scanf("%s", &(x->authorName));
    printf("Podaj nazwe ksiazki: ");
    scanf("%s", &(x->title));
    printf("Podaj nr katalogowy: ");
    scanf("%d", &(x->catalogNumber));
    printf("Podaj cene: ");
    scanf("%d", &(x->price));
}

void addBook(struct book **x)
{
    // firstBook = *x
    struct book *pointer;
    pointer = *x;
    if (pointer == NULL)
    {
        pointer = malloc(sizeof(struct book));
        loadBook(pointer);
        pointer->next = NULL;
        *x = pointer;
    }
    else
    {
        while (pointer->next != NULL)
        {
            pointer = pointer->next;
        }
        pointer->next = malloc(sizeof(struct book));
        pointer = pointer->next;
        loadBook(pointer);
        pointer->next = NULL;
    }
}


void printBooks(struct book **x)
{
    // firstBook = *x
    struct book *pointer;
    pointer = *x;
    clear();
    if (pointer == NULL)
    {
        printf("Lista pusta!\n\n");
        printf("Nacisnij dowolny klawisz aby powrocic do menu...\n");
        getch();
    }
    else
    {
        printf("Autor: %s\n", pointer->authorName);
        printf("Tytul: %s\n", pointer->title);
        printf("Nr katalogowy: %d\n", pointer->catalogNumber);
        printf("Cena: %d\n", pointer->price);
        printf("\n\n");
        while(pointer->next != NULL)
        {
            pointer = pointer->next;
            printf("Autor: %s\n", pointer->authorName);
            printf("Tytul: %s\n", pointer->title);
            printf("Nr katalogowy: %d\n", pointer->catalogNumber);
            printf("Cena: %d\n", pointer->price);
            printf("\n\n");
        }
        printf("Nacisnij dowolny klawisz aby powrocic do menu...\n");
        getch();
    }
}

void showMenu()
{
    struct book *firstBook;
    firstBook = NULL;
    struct book **ptr;
    ptr = &firstBook;

    char x;
    while(1)
    {
        clear();
        printf("1. Dodaj ksiazke\n");
        printf("2. Wyswietl ksiazki\n");
        printf("3. Zakoncz\n");
        scanf("%c", &x);
        if(x == '1')
        {
            addBook(ptr);
        }
        else if (x == '2')
        {
            printBooks(ptr);
        }
        else if (x == '3')
        {
            break;
        }
    }
}

int main(void)
{
    showMenu();

    return 0;
}