Java二维数组实现州首府问答系统：数据结构、排序与输入验证

import java.util.Scanner;
import java.util.Arrays; // 用于方便打印数组

public class StateCapitalQuiz {

    public static void main(String[] args) {
        String[][] stateAndCapitals = {
                {"Alabama", "Montgomery"},
                {"Alaska", "Juneau"},
                {"Arizona", "Phoenix"},
                {"Arkansas", "Little Rock"},
                {"California", "Sacramento"},
                {"Colorado", "Denver"},
                {"Connecticut", "Hartford"},
                {"Delaware", "Dover"},
                {"Florida", "Tallahassee"},
                {"Georgia", "Atlanta"},
                {"Hawaii", "Honolulu"},
                {"Idaho", "Boise"},
                {"Illinois", "Springfield"},
                {"Indiana", "Indianapolis"},
                {"Iowa", "Des Moines"},
                {"Kansas", "Topeka"},
                {"Kentucky", "Frankfort"},
                {"Louisiana", "Baton Rouge"},
                {"Maine", "Augusta"},
                {"Maryland", "Annapolis"},
                {"Massachusetts", "Boston"},
                {"Michigan", "Lansing"},
                {"Minnesota", "Saint Paul"},
                {"Mississippi", "Jackson"},
                {"Missouri", "Jefferson City"},
                {"Montana", "Helena"},
                {"Nebraska", "Lincoln"},
                {"Nevada", "Carson City"},
                {"New Hampshire", "Concord"},
                {"New Jersey", "Trenton"},
                {"New Mexico", "Santa Fe"},
                {"New York", "Albany"},
                {"North Carolina", "Raleigh"},
                {"North Dakota", "Bismarck"},
                {"Ohio", "Columbus"},
                {"Oklahoma", "Oklahoma City"},
                {"Oregon", "Salem"},
                {"Pennsylvania", "Harrisburg"},
                {"Rhode Island", "Providence"},
                {"South Carolina", "Columbia"},
                {"South Dakota", "Pierre"},
                {"Tennessee", "Nashville"},
                {"Texas", "Austin"},
                {"Utah", "Salt Lake City"},
                {"Vermont", "Montpelier"},
                {"Virginia", "Richmond"},
                {"Washington", "Olympia"},
                {"West Virginia", "Charleston"},
                {"Wisconsin", "Madison"},
                {"Wyoming", "Cheyenne"}
        };

        System.out.println("原始州首府数据：");
        displayArray(stateAndCapitals); // 调用辅助方法显示数组内容
    }

    /**
     * 辅助方法：打印二维数组的内容
     * @param arr 要打印的二维字符串数组
     */
    public static void displayArray(String[][] arr) {
        for (int i = 0; i < arr.length; i++) {
            System.out.println(Arrays.toString(arr[i]));
        }
        System.out.println(); // 打印空行增加可读性
    }
}

// ... (接上面的StateCapitalQuiz类)

    public static void main(String[] args) {
        // ... (stateAndCapitals 数组初始化)

        System.out.println("原始州首府数据：");
        displayArray(stateAndCapitals);

        // 对数组进行冒泡排序，按首府名称（第二列）排序
        bubbleSortByCapital(stateAndCapitals);

        System.out.println("按首府名称排序后的数据：");
        displayArray(stateAndCapitals);
    }

    /**
     * 对二维字符串数组进行冒泡排序，根据第二列（首府名称）进行排序。
     * @param arr 要排序的二维字符串数组
     */
    public static void bubbleSortByCapital(String[][] arr) {
        int n = arr.length;
        for (int i = 0; i < n - 1; i++) {
            for (int j = 0; j < n - 1 - i; j++) {
                // 比较当前行和下一行的首府名称 (arr[j][1] 和 arr[j+1][1])
                // String.compareTo() 方法用于字符串比较，返回负数表示第一个字符串小于第二个
                if (arr[j][1].compareTo(arr[j+1][1]) > 0) {
                    // 如果当前首府大于下一首府，则交换整行数据
                    String[] temp = arr[j]; // 暂存当前行
                    arr[j] = arr[j+1];      // 将下一行移动到当前行
                    arr[j+1] = temp;        // 将暂存的当前行移动到下一