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java - 如何在更改方法中使用用户选择

问题描述

我正在制作一个自动售货机程序，但我不知道如何在我的 for 循环中使用用户选择，因为当我将选择放入循环时它会给我一个错误。 

public class PopGenerator {
    double price[] = {2.49, 1.25, 3.49, 3.25, 2,25, 1.30, 3.40, 3.49, 2.50, 3.00}; 

    public void beveragechoice()
    {
        Scanner c = new Scanner(System.in);
        int choice = c.nextInt();
        double price[] = {2.49, 1.25, 3.49, 3.25, 2.25, 1.30, 3.40, 3.49, 2.50, 3.00}; 
        switch(choice)
        {
        case 1:
            System.out.println("This beverage costs $" + price[0]);
            break;
        case 2:
            System.out.println("This beverage costs $" + price[1]);
            break;
        case 3: 
            System.out.println("This beverage costs $" + price[2]);
            break;
        case 4:
            System.out.println("This beverage costs $" + price[3]);
            break;
        case 5: 
            System.out.println("This beverage costs $" + price[4]);
            break;
        case 6: 
            System.out.println("This beverage costs $" + price[5]);
            break;
        case 7:
            System.out.println("This beverage costs $" + price[6]);
            break;
        case 8:
            System.out.println("This beverage costs $" + price[7]);
            break;
        case 9: 
            System.out.println("This beverage costs $" + price[8]);
            break;
        case 10:
            System.out.println("This beverage costs $" + price[9]);
        }
    }

    public void change()
    {
        System.out.println("Enter money put into the machine: ");
        Scanner m = new Scanner(System.in);
        int money = m.nextInt();

        for(int x = choice; x >= 0 ; x--)
            if (money == price[x])
            {
                System.out.println("No change.");
            }
            else
            {
                System.out.print("Your change is: ");
                System.out.print(money - price[x]);
            }
    }
}

标签： java

解决方案

您可以简化这两种方法以避免使用多个扫描器或通过它们传递变量，如下所示：

public void beveragechoice() {
    double prices[] = {2.49, 1.25, 3.49, 3.25, 2,25, 1.30, 3.40, 3.49, 2.50, 3.00};
    System.out.println("Select one beverage");
    Scanner c = new Scanner(System.in);
    int choice = c.nextInt();
    if (choice > 0 && choice <= prices.length) {
        double p = prices[choice - 1];
        System.out.println("This beverage costs $" + p);
        System.out.println("Enter money put into the machine: ");
        double money = c.nextDouble();
        if (money == p) {
            System.out.println("No change.");
        } else {
            System.out.println("Your change is: $" + (money - p));
        }
    }
}

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