私は宿題のために書店プログラムを書いています。プログラムは、ユーザーが選択できる6つの異なるオプションをユーザーに提供します。現在、私が取り組んでいるのはオプション 1 です。オプション 1 は、在庫に書籍を追加することです。ユーザーがオプション 1 を選択すると、書籍のタイトルを入力するように求められ、書籍の在庫があるかどうかが確認されます。私が抱えている問題は、ユーザーが入力した本のタイトルが既に在庫があるかどうかを確認することです。inStock という関数がありますが、この関数を呼び出す方法がわかりません。現在、if (bt == myBkStore.inStock(title, y))互換性のない型が原因であるという行でエラーが発生しているため、コードはコンパイルされません。しかし、inStock() 関数を呼び出す方法がわかりません。これまでの私のコーディングは次のとおりです。
import java.util.Scanner;
import java.util.ArrayList;
public class MyBookstore {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
Bookstore myBkStore = new Bookstore();
int y = 0;
int user_choice = 2;
boolean quit = false;
do {
//display menu to user
//ask user for his choice and validate it (make sure it is between 1 and 6)
System.out.println();
System.out.println("1) Add a book to the stock");
System.out.println("2) Sell a book in stock");
System.out.println("3) List the titles of all the books in stock (in the Bookstore object)");
System.out.println("4) List all the information about the books in stock (in the Bookstore object)");
System.out.println("5) Print out the gross income of the bookstore");
System.out.println("6) Quit");
System.out.println();
System.out.print("Enter choice [1-6]: ");
user_choice = s.nextInt();
switch (user_choice) {
case 1: System.out.println("Enter a book title");
String bt = s.next(); //stores title of book user enters in
if (myBkStore.inStock(title, y))
{
System.out.println("How many more to add to the stock");
y = s.nextInt();
myBkStore.addBookQuantity(bt, y);
}
else
{
System.out.println("Enter the amount of pages of the book: ");
int pages = s.nextInt();
System.out.println("Enter the price of the book: ");
double price = s.nextDouble();
System.out.println("Enter the quantity to add: ");
int quant = s.nextInt();
//myBkStore.Book(bt, pages, price, quant);
myBkStore.addNewBook(book);
}
break;
case 2: System.out.println("Enter book title to buy: ");
String bookT = s.next();
myBkStore.sellBook(title, y);
break;
case 3: myBkStore.listTitles();
break;
case 4: myBkStore.listBooks();
break;
case 5: myBkStore.getIncome();
break;
case 6: System.out.println("Thanks for coming");
quit = true;
break;
default: System.out.println("\nInvalid Choice");
}
}
while (!quit);
}
static class Bookstore {
private Book[] books; // all the books in this bookstore
private int totalBooks; // the number of books in this bookstore
private double grossIncome; //the gross income of the bookstore (will be incremented when books are sold)
// Constructor: A new Bank object initially doesn’t contain any accounts.
public Bookstore() {
books = new Book[100];
totalBooks = 0;
grossIncome = 0;
}
// Creates a new bank account using the customer name and the opening balance given as parameters
// and returns the account number of this new account. It also adds this account into the account list
// of the Bank calling object.
public void addNewBook(Book b) {
if(totalBooks < books.length) {
books[totalBooks] = b;
totalBooks++;
}
else
{
System.out.println("\nSorry, cannot add book to stock.");
}
}
public void addBookQuantity(String title, int quantity) {
for (int i =0; i<totalBooks; i++) {
if (title == books[i].getTitle() ) {
books[i].addQuantity(quantity);
System.out.println("Quantity added successfully");
return;
}
}
/*int i;
for (i = 0; i < totalbooks; i++)
{
if((books[i].getTitle()).equals(title))
{
books[i].addQuantity(quantity);
return;
}
}*/
}
public boolean inStock (String title, int quantity) {
for (int i =0; i<totalBooks; i++) {
if (title.equals(books[i].getTitle())) {
if (quantity <= books[i].getQuantity()) {return true;}
else {return false;}
}
}
return false;
}
public boolean sellBook(String title, int quantity){
int i;
boolean sellflag=false;
// Checks to see if the books are in stock.
boolean retval = inStock(title, quantity);
// If so, completes the sale.
if (retval) {
for (i=0; i<totalBooks && !sellflag; i++) {
if (title.equals(books[i].getTitle())) {
books[i].subtractQuantity(quantity);
grossIncome += (books[i].getPrice()) * quantity;
sellflag = true;
}
} // for
} // if
return retval;
} // sellBook
public void listTitles()
{
for (int i = 0; i < totalBooks; i++)
{
System.out.println(books[i].getTitle());
}
}
public void listBooks()
{
int i;
System.out.println("\nList of Books\n======");
for (i = 0; i < totalBooks; i++)
{
System.out.println(books[i]);
}
System.out.println();
}
public double getIncome()
{
return grossIncome;
}
}
static class Book{
private String title;
private int numOfPages;
private double price;
private int quantity;
private Book book;
public String toString(){
return "Title: " + title + "\nNumber of pages: " + numOfPages + "\nPrice:" + price +"\nQuantity: " + quantity + "\n";
}
public Book book(String thetitle, int pages, double cost, int num){
/*title = thetitle;
numOfPages = pages;
price = cost;
quantity = num;*/
return book;
}
public String getTitle(){
return title;
}
public double getPrice(){
return price;
}
public int getQuantity(){
return quantity;
}
public void addQuantity(int amount){
quantity = quantity + amount;
}
public void subtractQuantity(int amount)
{
System.out.println("Amount to buy");
Scanner s = new Scanner(System.in);
quantity = s.nextInt();
quantity = quantity - amount;
}
}//end of class
}