Нужер прогу прочитать досканально Cpp( для чайников)

Препод будет спрашивать как работает прога, будет тыкать пальцем в прогу и спрашивать че это, как это работает, что оно делает...крч, хелп

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

struct Book {
char author[30];
char title[30];
int pages;
int pubYear;
int copies;
};

void allocList(struct Book **bookList, int bookAmount);
void fillKeyboard(struct Book *bookList, int bookAmount);
void printList(struct Book *bookList, int bookAmount);
void writeStruct(struct Book *bookList, int bookAmount);
void readStruct(struct Book *bookList, int bookAmount);
void printChoices(void);

void addBook(struct Book *bookList, int bookIndex);
void editBook(struct Book *bookList, int bookIndex);
int deleteBook(struct Book **bookList, int bookAmount, int bookIndex);

void deallocateMemory(struct Book **bookList, int bookAmount);

struct Book findBook(struct Book *bookList, int bookAmount, char* title);

int addToEnd(struct Book **bookList, int bookAmount);
int insertBook(struct Book **bookList, int bookAmount, int bookIndex);
int sortBooks(struct Book *bookList, int bookAmount);

void quit(void);

int main(void) {

struct Book *booksList = NULL;
int bookAmount = 0;

int insertionIndex = 0;
int deletionIndex = 0;
int indexToChange = 0;

char bookToFind[20];

int choice;

printChoices();

while (1) {

printf("enter your choice: ");
scanf("%d", &choice);

switch(choice) {
case 1:
printf("enter amount of books to hold: ");
scanf("%d", &bookAmount);
allocList(&booksList, bookAmount);
break;
case 2:
fillKeyboard(booksList, bookAmount);
break;
case 3:
printList(booksList, bookAmount);
break;
case 4:
writeStruct(booksList, bookAmount);
break;
case 5:
readStruct(booksList, bookAmount);
break;
case 6:
bookAmount = addToEnd(&booksList, bookAmount);
break;
case 7:
printf("enter index where to insert: ");
scanf("%d", &insertionIndex);
bookAmount = insertBook(&booksList, bookAmount, insertionIndex);
break;
case 8:
printf("enter index of element to delete: ");
scanf("%d", &deletionIndex);
bookAmount = deleteBook(&booksList, bookAmount, deletionIndex);
break;
case 9:
printf("enter index of element to change: ");
scanf("%d", &indexToChange);
editBook(booksList, indexToChange);
break;
case 10:
printf("enter title of the book that you want to find: ");
scanf("%s", &*bookToFind);
findBook(booksList, bookAmount, bookToFind);
break;
case 11:
sortBooks(booksList, bookAmount);
break;
case 12:
printChoices();
break;
case 13:
deallocateMemory(&booksList, bookAmount);
break;
case 14:
quit();
break;
default:
printf("are you sure you entered the right command?\nEnter 12 to list available choices \n");
}
}

return 0;
}

void allocList(struct Book **bookList, int bookAmount) {
*bookList = malloc(sizeof(struct Book) * bookAmount);
printf("memory for %d books was allocated \n", bookAmount);
}

void fillKeyboard(struct Book *bookList, int bookAmount) {

int i = 0;

while (bookAmount--) {
addBook(bookList, i++);
}

}

void addBook(struct Book *bookList, int bookIndex) {

char authorName[30], title[30];

printf("enter information about the book \n");

printf("enter author: ");
scanf("%s", *&authorName);
strcpy(bookList[bookIndex].author, authorName);

printf("enter title: ");
scanf("%s", *&title);
strcpy(bookList[bookIndex].title, title);

printf("enter year of publication: ");
scanf("%d", &bookList[bookIndex].pubYear);

printf("enter amount of pages: ");
scanf("%d", &bookList[bookIndex].pages);

printf("enter amount of copies sold: ");
scanf("%d", &bookList[bookIndex].copies);
}

int addToEnd(struct Book **bookList, int bookAmount) {

*bookList = realloc(*bookList, (sizeof(bookList) + 1) * sizeof(struct Book));
addBook(*bookList, bookAmount);

return ++bookAmount;
}

void printList(struct Book *bookList, int bookAmount) {

for (int i = 0; i < bookAmount; i++) {

if (bookList == NULL) {
printf("nothing to print");
return;
}

printf("\n\tbook details");
printf("\n--------------------\n");
printf("author is: %s \n", bookList.author);
printf("title is: %s \n", bookList.title);
printf("amount of pages: %d \n", bookList.pages);
printf("published in: %d \n", bookList.pubYear);
printf("copies sold: %d \n", bookList.copies);
printf("--------------------\n");
}

}

struct Book findBook(struct Book *bookList, int bookAmount, char* title) {

int i;

for (i = 0; i < bookAmount; i++) {
if (strcmp(bookList[i].title, title) == 0) {
printf("found the book \n");
return bookList[i];
}
}

printf("sorry, the book was not found \n");
return bookList[i];
}

void writeStruct(struct Book *bookList, int bookAmount) {

FILE* outfile;

// open file for writing
outfile = fopen("output.txt", "wb");

if (outfile == NULL) {
fprintf(stderr, "error while openning the file \n");
exit(1);
}

fwrite(bookList, sizeof(struct Book), bookAmount, outfile);
fclose(outfile);
}

void readStruct(struct Book *bookList, int bookAmount) {

FILE* inputfile;

// open file for reading
inputfile = fopen("output.txt", "rb");

if (inputfile == NULL) {
fprintf(stderr, "error while openning the file \n");
exit(1);
}

fread(bookList, sizeof(struct Book), bookAmount, inputfile);
fclose(inputfile);
}

void editBook(struct Book *bookList, int bookIndex) {
printf("changing information of book number: %d \n", bookIndex + 1);
addBook(bookList, bookIndex);
}

int deleteBook(struct Book **bookList, int bookAmount, int bookIndex) {

if (bookIndex >= bookAmount) {
printf("Error, index is out of bounds\n");
return -1;
}

*bookList = realloc(*bookList, (sizeof(bookList) - 1) * sizeof(struct Book));

// left shift all elements
for (int i = bookIndex; i < bookAmount; i++) {
strcpy((*bookList)[i].author, (*bookList)[i + 1].author);
strcpy((*bookList)[i].title, (*bookList)[i + 1].title);
(*bookList)[i].pages = (*bookList)[i + 1].pages;
(*bookList)[i].pubYear = (*bookList)[i + 1].pubYear;
(*bookList)[i].copies = (*bookList)[i + 1].copies;
}

printf("book with number %d was successfully deleted \n", bookIndex + 1);
return --bookAmount;
}

int insertBook(struct Book **bookList, int bookAmount, int bookIndex) {

// book can be inserted at the end
if (bookIndex >= (bookAmount + 1)) {
printf("Error, index is out of bounds\n");
return -1;
}

// we should reallocate the memory to hold one more
*bookList = realloc(*bookList, (sizeof(bookList) + 1) * sizeof(struct Book));

int i;

// right shift all elements after given index
// to make space for a new one
for (i = bookAmount - 1; i >= bookIndex; i--) {
strcpy((*bookList)[i + 1].author, (*bookList)[i].author);
strcpy((*bookList)[i + 1].title, (*bookList)[i].title);
(*bookList)[i + 1].pages = (*bookList)[i].pages;
(*bookList)[i + 1].pubYear = (*bookList)[i].pubYear;
(*bookList)[i + 1].copies = (*bookList)[i].copies;
}

// add a new book
addBook(*bookList, bookIndex);

return ++bookAmount;
}

int sortBooks(struct Book *bookList, int bookAmount) {

if (bookAmount < 2) {
return 0;
}

printf("\n\t sorting\n");

struct Book temp;

int swapped;
int i = 0;

do {
swapped = 0;
for (i = 0; i < bookAmount - 1; i++) {
if (strcmp(bookList[i].title, bookList[i + 1].title) > 0) {
temp = bookList[i];
bookList[i] = bookList[i + 1];
bookList[i + 1] = temp;
swapped = 1;
}
}
} while (swapped);

return 0;
}

void deallocateMemory(struct Book **bookList, int bookAmount) {
free(*bookList);
*bookList = NULL;
printf("deallocated \n");
}

void quit() {

printf("are you sure you want to quit? y/n\n");

char choice;

do {
scanf("%c", &choice);
} while (choice != 'y' && choice != 'n');

if (choice == 'y') {
exit(0);
}

return;
}

void printChoices(void) {
printf("1\tAllocate memory \n");
printf("2\tFill books information from keyboard \n");
printf("3\tList all available books \n");
printf("4\tWrite books to the file \n");
printf("5\tRead books from the file \n");
printf("6\tAdd a book to the end \n");
printf("7\tInsert a book \n");
printf("8\tDelete a book \n");
printf("9\tEdit a book \n");
printf("10\tFind a book \n");
printf("11\tSort books by title \n");
printf("12\tList choices \n");
printf("13\tDeallocate memory\n");
printf("14\tExit\n");
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