比较字符串（用户键入他想要的任意多个），然后使用 for 循环判断哪个是第一个（基于哪个第一个字母先出现）

Question

首先我必须要求用户输入一个数字。该数字将决定他必须输入多少个句子（应该 >2 ），然后我必须比较这些句子。我必须告诉哪个先来（基于字母顺序）。这是我到目前为止所做的一切。我不知道如何比较字符串，因为我不知道用户将键入多少字符串并且没有它们的名称。

import java.util.*;

public class Sentences {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        int number = 0;
        while (number < 2) {
            System.out.println("Type a number > 2");
            number = scan.nextInt();
        }

        scan.nextLine();

        String sentence;
        int y = 0;
        for (int i = 0; i < number; i++) {
            System.out.println("Type a sentence");
            sentence = scan.nextLine();
        }
    }
}

Answer 1

你很接近。您需要一个数组 (sentences[]) 而不是单个变量 (sentence)，如下所示：

import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int number = 0;
        while (number < 2) {
            System.out.print("Type a number > 2: ");
            number = Integer.parseInt(scan.nextLine());
        }

        String[] sentences = new String[number];
        int y = 0;
        for (int i = 0; i < number; i++) {
            System.out.print("Type a sentence: ");
            sentences[i] = scan.nextLine();
        }
        Arrays.sort(sentences);
        for (String sentence : sentences) {
            System.out.println(sentence);
        }
    }
}

要对String sentences[]进行排序，您需要使用Arrays.sort(sentences)，如上所示。

样本运行:

Type a number > 2: 0
Type a number > 2: 3
Type a sentence: Hello world
Type a sentence: You are awesome
Type a sentence: My name is Jane
Hello world
My name is Jane
You are awesome

[更新]

根据您的说明，您只想打印按字母顺序排列最低的一个句子。这就像跟踪数字列表中的最小数字。

算法如下：

将第一个输入存储到变量，例如 lowestAlphabetical。
在循环中，将 lowestAlphabetical 的值与下一个输入进行比较，如果下一个输入的字母顺序较低，则将下一个输入放入 lowestAlphabetical。

演示：

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int number = 0;
        while (number < 2) {
            System.out.print("Type a number > 2: ");
            number = Integer.parseInt(scan.nextLine());
        }

        // Scan the first sentence
        System.out.print("Type a sentence: ");
        String sentence = scan.nextLine();

        // Since we have only one sentence till now, it is also the lowest in
        // alphabetical order
        String lowestAlphabetical = sentence;

        // Loop for next inputs
        for (int i = 1; i < number; i++) {
            System.out.print("Type the next sentence: ");
            sentence = scan.nextLine();
            if (sentence.compareTo(lowestAlphabetical) < 0) {
                lowestAlphabetical = sentence;
            }
        }
        System.out.println(lowestAlphabetical);
    }
}

样本运行:

Type a number > 2: 3
Type a sentence: Hello world
Type the next sentence: Good morning
Type the next sentence: My name is Jane
Good morning

比较字符串（用户键入他想要的任意多个），然后使用 for 循环判断哪个是第一个（基于哪个第一个字母先出现）

Comparing Strings ( the user types as many as he wants) and then telling which one is first (based on which first letter comes first) using for loop

java

string

for-loop

compare

compareto

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