最喜欢的食物 Java 程序出错了

Question

下面是我的 Java 程序。现在，程序正确运行的唯一方法是让最后一列最长。如果数组中的最后一列不是最长的，则输出不正确。例如，如果food 数组在第二列中的元素比在第三列中的元素多，如下所示：

String[][] food = {
        {"Bannana", "Apple", "Pear", "Orange"}, // fruits
        {"GreenBean", "Iceburg", "Spenach", "peas", "carrots", "potatoes", "beans"}, // vegetables 
        {"Steak",   "Baccon", "Beef", "TurkeyB", "TurkeyBacon", "Chicken"} // meats 
};

例如，如果输入 chicken 作为输入，则输出如下：

Yo have no favorite food
Your favorite food is Chicken

另外，如果输入是biscuit，那么输出是这样的：

Yo have no favorite food
Yo have no favorite food

那么，有没有办法只打印一次"Yo have no favorite food" 或正确打印出最喜欢的食物，而最后一列不必是最长的？

代码如下：

package com.begg;

import java.util.*;

public class List {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        String[][] food = {
                {"Bannana", "Apple", "Pear", "Orange"}, // fruits
                {"GreenBean", "Iceburg", "Spenach", "peas"}, // vegetables 
                {"Steak",   "Baccon", "Beef", "TurkeyB", "TurkeyBacon", "Chicken"} // meats 
        };

        for(int row = 0; row < food.length; row++) {
            for (int col = 0; col < food[row].length; col ++) {
                System.out.print(food[row][col] + ", ");
            }
            System.out.println();
        }
        System.out.println("Enter your favorite out of the options above:");
        String k = sc.next();
        loop2:
        for(int row2 = 0; row2<food.length; row2++) {
            for (int col2 = 0; col2< food[row2].length; col2++) {
                if (k.equalsIgnoreCase(food[row2][col2])) {
                    System.out.println("Your favorite food is " + food[row2][col2]);
                    break loop2;
                }
                else if (!(k.equalsIgnoreCase(food[row2][col2])) & col2== 5 ) {
                    System.out.println("Yo have no favorite food");
                }
            }
        }

    }
}

谢谢！

Answer 1

改变这部分：

else if (!(k.equalsIgnoreCase(food[row2][col2])) & col2== 5 ) {
    System.out.println("Yo have no favorite food");
}

到这里：

else if (!(k.equalsIgnoreCase(food[row2][col2])) && row2 == food.length-1 && col2 == food[row2].length-1) {
    System.out.println("Yo have no favorite food");
}

应该做我认为你正在寻找的东西。编辑后的else if 会检查数组的所有值是否都已检查（不管哪一列更长），如果没有匹配输入，那么它将执行一次System.out.println("Yo have no favorite food");。

Answer 2

使用 Hashset 而不是两个 for 来迭代 2d array。类似的代码;

import java.util.HashSet;
import java.util.Scanner;

public class List {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        String[][] food = {
                {"Bannana", "Apple", "Pear", "Orange"}, // fruits
                {"GreenBean", "Iceburg", "Spenach", "peas"}, // vegetables
                {"Steak", "Baccon", "Beef", "TurkeyB", "TurkeyBacon", "Chicken"} // meats

                /*
                 * Your longest part of your array should be the longest
                 * if it's not, using the length  of the column to end a loop may cause problems
                 * if you use the row instead, everything after the row three will execute
                 *
                 */


        };

        for (int row = 0; row < food.length; row++) {
            for (int col = 0; col < food[row].length; col++) {
                System.out.print(food[row][col] + ", ");
            }
            System.out.println();
        }

        System.out.println("Enter your favorite out of the options above:");
        String k = sc.next();

        final HashSet<Object> setOfFood = new HashSet<>();
        //Add all food to hashset
        for (String[] subFoodList : food) {
            for (String subFood : subFoodList) {
                setOfFood.add(subFood.toLowerCase());
            }
        }

        //if set containts scanners string returns relevant response
        if (setOfFood.contains(k.toLowerCase())) {
            System.out.println("Your favorite food is " + k);
        } else {
            System.out.println("Yo have no favorite food");
        }

    }
}