117 lines
4.0 KiB
Java
117 lines
4.0 KiB
Java
import java.util.Scanner;
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/*
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You could also use "import drinks.*" instead of the 4 lines below
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*/
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import drinks.Beer;
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import drinks.Coke;
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import drinks.Drink;
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import drinks.GreenTea;
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public class VendingMachine {
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private static final Drink[] availableDrinks = new Drink[3];
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int drinkSelection = 0;
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public VendingMachine() {
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availableDrinks[0] = new Beer();
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availableDrinks[1] = new Coke();
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availableDrinks[2] = new GreenTea();
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}
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public double selectDrink() {
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drinkSelection = presentDrinkMenu() - 1; // This " - 1 " is to keep "drinkSelection" within the "availableDrinks" array range
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return availableDrinks[drinkSelection].getPrice();
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}
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public double insertCoins() {
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double amount = 0.0;
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Scanner sc = new Scanner(System.in);
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printCoinOptions();
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do {
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char coin = sc.next().charAt(0);
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amount += processCoinAmount(coin);
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System.out.printf("Coins inserted: %.2f \n", amount);
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} while (amount < availableDrinks[drinkSelection].getPrice());
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return amount;
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}
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public void checkChange(double amount)
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{
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double change = 0.0;
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if (amount > availableDrinks[drinkSelection].getPrice())
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{
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change = amount - availableDrinks[drinkSelection].getPrice();
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System.out.printf("Change $ %.2f \n", change);
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}
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}
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public void printReceipt()
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{
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System.out.println("Please collect your drink");
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System.out.println("Thank you!!");
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}
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private Integer presentDrinkMenu() {
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Scanner sc = new Scanner(System.in);
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int drinkSelection;
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System.out.print("====== Vending Machine ====== \n");
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/*
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Note. The for loop below is just an enhanced way of writing the following:
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for (int i = 0; i < availableDrinks.length; i++) {
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System.out.printf("|%d. Buy %s ($%.2f) \n", i + 1, availableDrinks[i].getName(), availableDrinks[i].getPrice());
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}
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*/
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int i = 1;
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for (Drink drink : availableDrinks) {
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System.out.printf("|%d. Buy %s ($%.2f) \n", i++, drink.getName(), drink.getPrice());
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}
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System.out.print("|============================ \n");
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do {
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System.out.println("Please enter selection: ");
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drinkSelection = sc.nextInt();
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} while (drinkSelection < 1 || drinkSelection > (availableDrinks.length + 1));
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return drinkSelection;
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}
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private void printCoinOptions() {
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System.out.println("Please insert coins: ");
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System.out.println("========== Coins Input ===========");
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System.out.println("|Enter 'Q' for ten cents input |");
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System.out.println("|Enter 'T' for twenty cents input|");
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System.out.println("|Enter 'F' for fifty cents input |");
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System.out.println("|Enter 'N' for a dollar input |");
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System.out.println("==================================");
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}
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private double processCoinAmount(char coin) {
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/*
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Note. The code below is just an enhanced way of writing the following:
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switch (coin)
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{
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case 'Q': case 'q': return 0.10;
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case 'T': case 't': return 0.20;
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case 'F': case 'f': return 0.50;
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case 'N': case 'n': return 1.00;
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}
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return 0.0;
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This enhanced way or writing switch-cases was introduced in Java 12 and Java 13 (we are currently at Java LTS 22, with Java 23 and Java 24 under early-access);
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The "->" was introduced in Java 8. It denotes a Lambda expression: https://www.w3schools.com/java/java_lambda.asp
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The Switch with a lambda-like syntax expression was introduced in Java 14: https://www.javacodegeeks.com/2020/05/switch-as-an-expression-in-java-with-lambda-like-syntax.html
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*/
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return switch (coin) {
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case 'Q', 'q' -> 0.10;
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case 'T', 't' -> 0.20;
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case 'F', 'f' -> 0.50;
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case 'N', 'n' -> 1.00;
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default -> 0.0;
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};
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}
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} |