Java数组索引超出范围？

Question

有人可以帮我解决下面发布的错误吗？ 该程序运行，但在调用显示捐赠时，我收到关于我的主要的错误。 我怎么能解决这个问题呢？ 是否与语法错误有关？ 这是我第一次使用数组，所以我欢迎有关良好习惯的反馈。 谢谢！

 Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 6
        at donations.processDonations(donations.java:78)
        at donations.main(donations.java:33)

    import java.util.Scanner; //needed for input

    public class donations {
        static double[] cashDonations = new double[6]; // stores the cash donations
                                                        // from 6 sites
        static double[] lbsFood = new double[6]; // stores the pounds of food
                                                    // donated from 6 sites
        static String[] siteName = new String[6]; // stores the names of the 6 sites
        static String bestSiteCash = " "; // stores the site name with the highest
                                            // cash donation
        static String bestSiteFood = " "; // stores the site name with the highest
                                            // food donation
        static double totalCash = 0; // stores the total cash collected for all
                                        // sites
        static double totalFood = 0; // stores the total food pounds collected for
                                        // all sites
        static double maxFood = 0; // store the highest food collection
        static double maxCash = 0; // stores the highest cash collection

        public static void main(String[] args) {

            Scanner input = new Scanner(System.in); // needed for input
            String anotherCourse = "yes"; // variable to control running program
                                            // again
            do {

                getDonations();
                processDonations();
                displayDonations();

                // This code ends the do while to run again
                System.out.print("Enter yes if you want to run again: ");
                anotherCourse = input.next();
                input.nextLine(); // causes skipping issue to fix
                System.out.print("\n\n\n");
            } while (anotherCourse.equalsIgnoreCase("yes"));

        } // end of main

        public static void getDonations() {
            Scanner input = new Scanner(System.in); // needed for input
            // Prompt user for site info
            for (int i = 0; i < 6; i++) {
                System.out.println("Enter site " + (i + 1) + " name: ");
                siteName[i] = input.next();

                System.out.println("Enter cash donation(USD) for " + siteName[i]
                        + ": ");
                cashDonations[i] = input.nextDouble();
                // double [] cashDonations = new double [6]; You have this already
                // at the top
                // int i;
                // for (i = 0 ; i < 6 ; i++)

                // cashDonations[i] = input.nextDouble();

                // double [] lbsFood = new double [6];
                System.out.println("Enter food donation(lbs.) for " + siteName[i]
                        + ": ");
                lbsFood[i] = input.nextDouble();

            }

        }

        public static void processDonations() {
            totalCash = 0;
            totalFood = 0;
            maxCash = cashDonations[0];
            maxFood = lbsFood[0];

            totalCash = cashDonations[1] + cashDonations[2] + cashDonations[3]
                    + cashDonations[4] + cashDonations[5] + cashDonations[6];
            totalFood = lbsFood[1] + lbsFood[1] + lbsFood[2] + lbsFood[3]
                    + lbsFood[4] + lbsFood[5] + lbsFood[6];

        }

        public static void displayDonations() {
            System.out.print("Total Cash Donations are " + totalCash);
            System.out.print("Total Food Donations are " + totalFood);
            System.out.print("Donation totals for " + siteName[1]);
            System.out.print("Total cash: " + cashDonations[1]);
            System.out.print("Food donations " +lbsFood[1]);
            System.out.println();
            System.out.print("Donation totals for " + siteName[2]);
            System.out.print("Total cash: " + cashDonations[2]);
            System.out.print("Food donations " +lbsFood[2]);
            System.out.println();
            System.out.print("Donation totals for " + siteName[3]);
            System.out.print("Total cash: " + cashDonations[3]);
            System.out.print("Food donations " +lbsFood[3]);
            System.out.println();
            System.out.print("Donation totals for " + siteName[4]);
            System.out.print("Total cash: " + cashDonations[4]);
            System.out.print("Food donations " +lbsFood[4]);
            System.out.println();
            System.out.print("Donation totals for " + siteName[5]);
            System.out.print("Total cash: " + cashDonations[5]);
            System.out.print("Food donations " +lbsFood[5]);
            System.out.println();
            System.out.print("Donation totals for " + siteName[6]);
            System.out.print("Total cash: " + cashDonations[6]);
            System.out.print("Food donations " +lbsFood[6]);
            System.out.println();

        }// end of displayDonations()

    }// end of class

Answer 1

static double[] cashDonations = new double[6];

这是一个有6个空格的数组，正确。 然而：

maxCash = cashDonations[0];
totalCash = cashDonations[1] + cashDonations[2] + cashDonations[3] + cashDonations[4] + cashDonations[5] + cashDonations[6];

在这里，您正在访问7个空格。 0,1,2,3,4,5和6。

Answer 2

您的代码中有几个位置，您可以直接在代码中引用索引6 。 以下是一些：

System.out.print("Donation totals for " + siteName[6]);
System.out.print("Total cash: " + cashDonations[6]);
System.out.print("Food donations " +lbsFood[6]);

但是所有的数组都被声明为长度为6 。

static double[] cashDonations = new double[6]; // stores the cash donations
                                                    // from 6 sites
static double[] lbsFood = new double[6]; // stores the pounds of food
                                                // donated from 6 sites
static String[] siteName = new String[6];

Java中的数组是从0开始的 ，因此长度为n的数组在这里只有索引0到n - 1或0到5 。 如果需要索引6 ，请使数组长度为7 。

Answer 3

我注意到你已经做了一个共同的“一个一个”的错误¯\\ _（ツ）_ /¯

在这里你已经正确地声明了3个大小为6的数组：

    static double[] cashDonations = new double[6]; 

    static double[] lbsFood = new double[6]; 

    static String[] siteName = new String[6];

虽然每个数组确实有6个元素，但第一个元素被称为0

[0]，[1]，[2]，[3]，[4]，[5]

在你的代码中，你调用了不存在的第7个元素“[6]”：

   totalCash = cashDonations[1] + cashDonations[2] + cashDonations[3]
                + cashDonations[4] + cashDonations[5] + cashDonations[6];

   totalFood = lbsFood[1] + lbsFood[1] + lbsFood[2] + lbsFood[3]
                + lbsFood[4] + lbsFood[5] + lbsFood[6];

要修复它，您只需要将元素从0到5：

   totalCash = cashDonations[0] + cashDonations[1] + cashDonations[2]
                + cashDonations[3] + cashDonations[4] + cashDonations[5];

   totalFood = lbsFood[0] + lbsFood[1] + lbsFood[2]
                + lbsFood[3] + lbsFood[4] + lbsFood[5];

这是一个容易犯的错误，因为我们被教导说0在我们的整个生命中都没有价值。

继续编程，不要放弃！