我如何允许用户输入任意数量的字符串，同时根据数组检查它

Question

我正在为我的CSCI 1301课程做这个作业，我有点卡住了。任务是编写一个程序，该程序将向用户提供服务列表，并允许他们选择他们想要的任何或所有服务并显示最终价格。这是我到目前为止的代码，

public static void carMaintenance()
{
Scanner sc = new Scanner(System.in);
String makeOfCar;
System.out.println("What's the make of your car?");
makeOfCar = sc.next();
String[] services = {"Oil Change", "Tire Rotation", "Air Filter", "Fluid Check"};
double[] prices = {39.99, 49.99, 19.99, 10.99};
System.out.println("What services whould you like for your "+makeOfCar+"?");
System.out.println(services[0]+", "+services[1]+", "+services[2]+", "+services[3]+".");
}

我陷入困境的是，我将如何允许用户请求他们想要的任意数量的服务？(从逻辑上讲，他们最多只能请求 4 个服务(

我想我可以使用另一个数组并将其放在"do-while"循环中来实现这一点，但是，一旦我根据"服务"数组检查它，我将如何为用户请求的每个服务分配价格，以便我可以计算所有请求服务的总价格？

任何见解和帮助将不胜感激！

Answer 1

您可以在额外的变量中跟踪总和。因此，您使用额外数组来检查重复项的想法仍然有效。检查是否已选择服务，如果没有，则将所选索引添加到总和中。

public static void carMaintenance() {
    Scanner sc = new Scanner(System.in);
    String makeOfCar;
    System.out.println("What's the make of your car?");
    makeOfCar = sc.nextLine();
    String[] services = {"Oil Change", "Tire Rotation", "Air Filter", "Fluid Check"};
    double[] prices = {39.99, 49.99, 19.99, 10.99};
    double sum = 0;

    System.out.println("What services whould you like for your " + makeOfCar + "?");
    System.out.println(services[0] + ", " + services[1] + ", " + services[2] + ", " + services[3] + ".");
    String choice;
    //This array simply tracks true or false for chosen/not chosen. boolean arrays are initialized with all values false.
    boolean[] chosenServices = new boolean[services.length]; //Can only be as many elements as there are services. This way you don't have to change it when you add another service
    do {
        choice = sc.nextLine();
        int choiceIndex = getIndex(services, choice);
        if (choiceIndex < 0) break; //Choice doesn't exist. You will have to refine that and add messages
        if (!chosenServices[choiceIndex]) { //service not yet chosen
            chosenServices[choiceIndex] = true;
            sum += prices[choiceIndex];
        } else {
            System.out.println("Was already chosen!");
        }
    } while (!choice.toLowerCase().equals("exit")); //Or something similar
    System.out.printf("%.2f", sum); //Price with 2 digits 
}
public static int getIndex(String[] arr, String search) {
    for (int i=0; i<arr.length; i++) {
        if (search.equals(arr[i]))
            return i;
    }
    return -1;
}

正如其中一条评论中提到的，这只是一个粗略的实现。您可能希望使用用户的索引输入来执行此操作，您可能希望检查比我在这里更精确的错误输入等，但这应该符合我认为您的意思。