Can anyone please help me complete the definition of BOOK STRUCT and implement the three functions in order for the program to work? Thank You. Code: #include <iostream> using namespace std; /* Struct to define a book */ struct BOOK_STRUCT { }; /*Function Name: check_out_book Parameters: A book Purpose: Function checks out a book. Nothing is returned. */ void check_out_book (BOOK_STRUCT* book) { } /*Function Name: get_book_by_title Parameters: A library of books, a title, and the size of the library Purpose: Function returns a pointer to a book based on the title supplied by the user. If the book is not found, a null pointer is returned. */ BOOK_STRUCT* get_book_by_title (BOOK_STRUCT library[], char* title, int lib_size) { } /*Function Name: print_avail_books Parameters: A library of books and the size of the library Purpose: Function goes through the library and prints only those books which are not checked out. */ void print_avail_books (BOOK_STRUCT library[], int lib_size) { } int main() { char in_title[81]; // buffer to contain input from user BOOK_STRUCT* book; // a book pointer int choice=0; // used by the menu int NUM_BOOKS = 2; // number of books in the library // library data structure BOOK_STRUCT library[] = {{"Gods and Generals", "Jeff Shaara", "123", 0},{"Killer Angels", "Michael Shaara", "143", 0}}; // Output message to user cout<<"Welcome to Fraser Library"<<endl; // Loop until the user selects exit. do{ cout<<"Please select from the following options."<<endl; cout<<"1. Search for a book."<<endl; cout<<"2. Print available books."<<endl; cout<<"3. Checkout a book."<<endl; cout<<"4. Exit"<<endl; cout<<" > "; cin>>choice; //read input if(cin.good() && choice > 0 && choice < 5){ // Make sure choice is correct if(choice == 1 || choice == 3){ // selections require title of the book cin.ignore(); // need to ignore the character return from the previous cin cout<<"Please enter the title of the book."<<endl<<" > "; cin.getline(in_title,81); //read input from user book = get_book_by_title(library, in_title, NUM_BOOKS); // get book if (book == NULL) // The book is not in the library cout<<endl<<in_title<<" not found. Please try another title"<<endl<<endl; else if (book->checked_out == true) // The book is available but checked out cout<<endl<<"Sorry, "<<book->title<<" is checked out. Please try another title"<<endl<<endl; else if (choice == 1) // The book is available and it will be checked out cout<<endl<<book->title<<" by "<<book->author<<" is available."<<endl<<endl; else{ // The book is available cout<<endl<<book->title<<" is available. I'll check it out for you now."<<endl<<endl; check_out_book(book); } } else if(choice == 2){ // user wants to print the list of books print_avail_books(library, NUM_BOOKS); } else{ //user selected exit cout<<"Thanks for coming!"<<endl; return 0; } } else { //user provided something we can't understand cout<<endl<<"Sorry, I don't understand what you selected. Please try again"<<endl<<endl; choice = 1; // This just makes sure the user gets a chance make another selection } } while(choice < 4); return 0; }