Java error about turning sentence into camelCase

Question

I'm starting to code and trying to do a challenge of turning a sentence into camelCase. After some experimenting on my own, got to the following code:

package teste;

import java.util.Scanner;

public class Teste {
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Insert the sentence to be turned into camelCase: ");
        String entry = keyboard.nextLine();
        System.out.print("Insert the character that is used as space: ");
        String space = keyboard.nextLine();
        char current;
        char next;
        String output = null;
        for (int i=0; i<=entry.length(); i++){
            current = entry.charAt(i);
            next = entry.charAt(i+1);
            if (i == entry.length()){
                output += Character.toLowerCase(current);
            } else if (entry.substring(i, i+1).equals(space)){
                output += Character.toUpperCase(next);
                i++;
            } else {
                output += Character.toLowerCase(current);
            }
        }
        
        System.out.println("This sentence in camelCase is: " + output);
    }

}

There is an error I can't seem to avoid with the last index of the input, even with the first if structure made especially for it, and I can't find out why. Could anyone explain to me what I did wrong?

`i<=entry.length()` should be `i < entry.length()` Also would be helpful to post the error message. — OldProgrammer, Aug 20 '22 at 17:58
"There is an error I can't seem to avoid with the last index" please include entire error message. — Pshemo, Aug 20 '22 at 18:22

score 0 · Accepted Answer · answered Aug 20 '22 at 18:41

you should avoid StringIndexOutOfBoundsException exception in line 15 "entry.charAt(i+1)", This code will fix your error.

import java.util.Scanner;

public class Teste {


public static void main(String[] args) {
    Scanner keyboard = new Scanner(System.in);
    System.out.print("Insert the sentence to be turned into 
    camelCase: ");
    String entry = keyboard.nextLine();
    System.out.print("Insert the character that is used as 
    space: ");
    String space = keyboard.nextLine();
    char current;
    char next;
    String output = "";
    for (int i=0; i<entry.length()-1; i++){
        current = entry.charAt(i);
        next = entry.charAt(i+1);
        if (i == entry.length()-2){
            output += Character.toLowerCase(current);
        } else if (entry.substring(i, i+1).equals(space)){
            output += Character.toUpperCase(next);
            i++;
        } else {
            output += Character.toLowerCase(current);
        }
    }
    //here we test the last character
    int len=entry.length();
    current = entry.charAt(len-1);
    if(!entry.substring(len-1, len).equals(space)){
        output += Character.toLowerCase(current);
    }

    System.out.println("This sentence in camelCase is: " + 
    output);
    }
}

Thank you very much, your answer gave me the insight of the dumb mistake I was making (not considering the last index being its length - 1, since it begins at 0). I edited the code a little bit different than yours, cause it fails when the last word is just one letter, but it helped a lot! For it to work, it should use if(!entry.substring(len-2, len).equals(space)){ at line 30. — JPCaillot, Aug 22 '22 at 11:53
Happy it helped you, exactly I didn't treat the case of santences that contain just one letter or ended with words of one letter. — MrS, Aug 23 '22 at 00:18

Java error about turning sentence into camelCase

1 Answers1