从 Java 中的数组中添加价格？

Question

我的 Java class 即将进行的测试有一些复习题，我目前正在做的测试要求我们创建一个包含两个数组的咖啡馆菜单，一个包含菜单项目和其他价格。在询问用户他们想要菜单中的哪些项目之前，我们必须打印所有价格的平均值，然后最后打印项目的总和。

我的代码：

import java.util.Scanner;

public class cafeMenu {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int choice; 
        double total = 0;

        //Array for storing prices
        double [] cafePrice = new double[5];
        cafePrice[0]= 6.99;
        cafePrice[1]= 5.99;
        cafePrice[2]= 2.99;
        cafePrice[3]= 1.50;
        cafePrice[4]= 2.50;

        //Menu item array
        String [] cafeDrink = new String[5];
        cafeDrink[0] = "Macchiato";
        cafeDrink[1] = "Latte"; 
        cafeDrink[2] = "Americano";
        cafeDrink[3] = "Tea";
        cafeDrink[4] = "Cappichino";

        //Welcome user and gather their menu selection
        System.out.println("Welcome to our cafe! Please enjoy!");
        System.out.printf("The average pricing for our drinks is: %.2f \n", + cafeAvg( cafePrice));
        System.out.println("Please enter a menu selection:\n"
                + "0. Macchiato -- .99\n"
                + "1. Latte -- .99\n"
                + "2. Americano -- .99\n"
                + "3. Tea -- .50\n"
                + "4. Cappichino -- .50");
        choice = input.nextInt();

        //Add up the total
        for(int i = 0; i < cafePrice.length; i++ ) {
            if(choice == cafePrice[i]) {
                total += cafePrice[i];
            }
        }
        System.out.println("Your total is: " + total);
    }

    //Method for average menu price
    public static double cafeAvg(double[] array) {
        double sum = 0;
        double sum2 = 0;
        for(int i = 0; i < array.length; i++) {
            sum += array[i];
            sum2 = sum /array.length;
        }
        return sum2;
    }
}

我还没有设置一个 do while 循环来继续询问用户输入，因为我有点难以将价格加在一起。我想我在我的 for 循环中犯了一个错误，或者可能是一个逻辑错误？这是我不断得到的结果，无论做出什么选择：

Welcome to our cafe! Please enjoy!
The average pricing for our drinks is: 3.99
Please enter a menu selection:
0. Macchiato -- .99
1. Latte -- .99
2. Americano -- .99
3. Tea -- .50
4. Cappichino -- .50
4
Your total is: 0.0

如有任何想法，我们将不胜感激。

Answer 1

您做错了以下事情，

    if(choice == cafePrice[i]) {
        total += cafePrice[i];
    }

choice 是一个 int 而 cafeprice[i] 是一个 double ...而且它们代表不同的东西。我认为你实际上想做以下事情，

total += cafePrice[choice];

而不是整个 for 循环。

这段代码对我有用，

    public static void main(String args[]) {
        Scanner input = new Scanner(System.in);
    int choice; 
    double total = 0;

    //Array for storing prices
    double [] cafePrice = new double[5];
    cafePrice[0]= 6.99;
    cafePrice[1]= 5.99;
    cafePrice[2]= 2.99;
    cafePrice[3]= 1.50;
    cafePrice[4]= 2.50;

    //Menu item array
    String [] cafeDrink = new String[5];
    cafeDrink[0] = "Macchiato";
    cafeDrink[1] = "Latte"; 
    cafeDrink[2] = "Americano";
    cafeDrink[3] = "Tea";
    cafeDrink[4] = "Cappichino";

    //Welcome user and gather their menu selection
    System.out.println("Welcome to our cafe! Please enjoy!");
    System.out.printf("The average pricing for our drinks is: %.2f \n", + cafeAvg( cafePrice));
    System.out.println("Please enter a menu selection:\n"
            + "0. Macchiato -- .99\n"
            + "1. Latte -- .99\n"
            + "2. Americano -- .99\n"
            + "3. Tea -- .50\n"
            + "4. Cappichino -- .50");
    choice = input.nextInt();

    //Add up the total
    total += cafePrice[choice];
    System.out.println("Your total is: " + total);
    }

    //Method for average menu price
public static double cafeAvg(double[] array) {
    double sum = 0;
    double sum2 = 0;
    for(int i = 0; i < array.length; i++) {
        sum += array[i];
        sum2 = sum /array.length;
    }
    return sum2;
}

从 Java 中的数组中添加价格？

Adding up prices from an Array in Java?

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