.indexOf "-1" is being skipped by my if statement

Question

Here I separate a string into separate words and then add "ay" to the end of each word if it contains a vowel, however the problem is when I reach the last word indexOf is -1so it is automaticly skipped by my if statement. To fix this I tried adding an if (i ==-1) however when I stepped through it with the debugger it automatically skips this if statement! Does anybody know why? And how can work around this issue and add "ay" to the last word even if .indexOf is -1

Method:

    public static void pigLatin(String sentence){
    sentence = sentence.trim();

    if(sentence.length()> 0){
        int i = sentence.indexOf(" ");
        String word = sentence.substring(0, i);
        if(i == -1){ //this  if statement is ignored
            if (word.contains("a") || word.contains("i") || word.contains("o") || word.contains("e") || word.contains("u")){
                System.out.println(word + "ay");
            } else{
                System.out.println(word);
            }
        }
        if(i != -1){
            if(word.contains("a") || word.contains("i") || word.contains("o") || word.contains("e") || word.contains("u")){
                System.out.println(word + "ay");
                pigLatin(sentence.substring(i));
            } else if(!word.contains("a") || !word.contains("i") || !word.contains("o") || !word.contains("e") || !word.contains("u")){
                System.out.println(word);
                pigLatin(sentence.substring(i));
            }
        }
    }
}

Main:

public class Main {
public static void main (String [] args){
    Scanner in = new Scanner(System.in);
    String word = in.nextLine();
    Functions.pigLatin(word);
  }
}

Answer 1

I see two problems.

• The two lines that say pigLatin(sentence.substring(i)) should say pigLatin(sentence.substring(i+1)) - otherwise you just see the same space over and over.
• the line that says else if(!word.contains("a") || ... COULD just say else, but if you insist on writing it in full, you must use && where you have ||.