Loop expects an input, while it should've iterated through every word of previous input

Question

Need to change every word, that starts with vowel to the longest one. Everything seems ok, however have faced with an unexpected behaviour from the loop, when I enter into it - scanner wants an input (7th line). Instead of asking for an input, it should iterate through every element (word) from the sentence I've set previously (2nd line). I do assume, that I've missed something.

    Scanner sc = new Scanner(System.in);
    String textToFormat = sc.nextLine();
    Pattern pattern = Pattern.compile(regex);
    Matcher matcher = pattern.matcher(textToFormat);

    while (sc.hasNext()) {
      currentWord = sc.next();
      if (currentWord.length() > longestWord.length()) {
        longestWord = currentWord;

      } else break;
    }

so what is the sc.hasNext and sc.next for? Just call the split method on the textToFormat String — Stultuske, Mar 09 '20 at 14:23
related: [What's the difference between next() and nextLine() methods from Scanner class?](https://stackoverflow.com/questions/22458575/whats-the-difference-between-next-and-nextline-methods-from-scanner-class) — jhamon, Mar 09 '20 at 14:23
@jhamon how is that related? he shouldn't be calling hasNext, nor the next() method — Stultuske, Mar 09 '20 at 14:24
@Stultuske Read your own comment to know how it's related. Then check the linked answer. — jhamon, Mar 09 '20 at 14:28

solid.py · Accepted Answer · 2020-03-09T14:39:51.820

By looking at your code, I see you are trying to find the longest string in a sentence inputted by user.
There is no need to input every word individually when you simply could input the entire line. Something like the following code could help you:

import java.util.Scanner;

public class Main {

    public static String findLongestWord(String[] arr){
        String longest = "";
        for (String current : arr){
            // If the current word is larger than the longest.
            if(current.length() > longest.length()){
                longest = current; // Then set longest word to current.
            }
        }
        return longest;
    }

    public static void main(String[] args) {
        // Get the sentence from the user.
        System.out.println("Input a sentence: ");
        Scanner scan = new Scanner(System.in);
        String s = scan.nextLine();
        // Split sentence into words.
        String[] arr = s.split("\\W+");
        System.out.println("Longest word is " + findLongestWord(arr));
    }
}

When run with input Find the longest word in this large sentence this outputs:

Input a sentence: 
Find the longest word in this large sentence.
Longest word is sentence

Never thought of splitting sc.nextLine() into an array of Strings. Works just fine. Still trying to realize why did I choose that while loop for iterating, guess need to refresh my knowledge about it. Thanks — her0ftheday, Mar 09 '20 at 14:47
@her0ftheday Thank you for the upvote and accept. PS: If you don't use `nextLine()` you basically input a word one-by-one which is something not inherently wrong but still tedious. — solid.py, Mar 09 '20 at 14:48

Loop expects an input, while it should've iterated through every word of previous input

1 Answers1