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

Question

First I have to ask the user to type a number. That number will decide how many sentences he has to type (should be >2 ) and then I have to compare those sentences. I have to tell which one comes first ( based on alphabet letters order). This is all I have done so far. I don't know how to compare Strings since I don't know how many the user will type and don't have names for them.

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

You were close. Instead of a single variable(sentence), you need an array(sentences[]) as shown below:

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);
        }
    }
}

To sort String sentences[], you need to use Arrays.sort(sentences) as shown above.

A sample run:

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

[Update]

As per your clarification, you wanted to print only one sentence which is the lowest in alphabetical order. It is like tracking the minimum number from a list of numbers.

The algorithm is as follows:

1. Store the first input to a variable, say lowestAlphabetical.
2. In a loop, compare the value of lowestAlphabetical with the next input and if the next input is lower in alphabetical order put the next input into lowestAlphabetical.

Demo:

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);
    }
}

A sample run:

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