String index out of range

[Juan Villena]

im having problems to figure it out where is probl
everytime i run this, string index out of range comes out as an error.

any suggestion please.

Thanks a lot.

import java.util.Scanner;
import java.lang.String;
public class DisplayVowels 
{
   public static void main(String[] args)
{
   Scanner keyboard = new Scanner(System.in);
   System.out.println("Enter a sentence: ");
   String sentence = keyboard.next();
   String vowelStr = "";

      System.out.println("You entered: " + sentence);
       int vowelCnt = 0;
       for (int ltr=0; ltr <= sentence.length(); ltr++){
        if (sentence.charAt(ltr)=='a' ||
               sentence.charAt(ltr)=='e' ||
               sentence.charAt(ltr)=='i' ||
               sentence.charAt(ltr)=='o' ||
               sentence.charAt(ltr)=='u'){
               vowelCnt++;
               vowelStr += sentence.charAt(ltr);
        }
      }
          System.out.println("The number of vowels is " + vowelCnt + " and they are: " + vowelStr);
  }
}

[Zandis Murāns]

This line is problematic:

for (int ltr=0; ltr <= sentence.length(); ltr++)

You're trying to access more char elements than you'r string has (as array's numbering starts at zero not one).
Try to change this line to this:

for (int ltr=0; ltr < sentence.length(); ltr++)

[fred rosenberger]

I added code tags to your post, making it easier to read. Next time, just highlight your java and click the "code" button - just like you were making it italic or bold.

Fixing this problem is simple enough. If a String has a length of 10, the characters are at positions 0-9. Your for loop should be "<", not "<=".

correct that, and you will find your next problem that needs fixing...

[Grayson Churchel]

Try changing your For statement to:
for (int ltr=0; ltr < sentence.length(); ltr++)
Since the string has a zero-based index (positions are 0 through n-1), your For statement is trying to index one place past the end of the string.
Example:
"Hello" : 0=H, 1=e, 2=l, 3=l, 4=o and 5=(error)
but the length of the string is 5 so you have to stop indexing through it at 4.

[Juan Villena]

Thanks a lot guys, i don't have that error message anymore, and i understand now
but when i enter " Its April" , it just take the lowercase vowel

do i have to write a statement using equalsIgnoreCase() ??

[Grayson Churchel]

Then you need to either add more test cases for capitol vowels, OR lower-case the character you're testing so that the upper-case char's will be caught. I believe there's a function which will ensure the characters are lower case before you do the compare.
Remember, Java is case-sensitive.

[Juan Villena]

Thanks a lot
i just did it and it works

[Grayson Churchel]

Happy to help.

[Campbell Ritchie]

Another way to do it

Set<Character> vowels;
 . . .
vowels = new HashSet<>(); // The <> operator only works in Java7; otherwise write <Character>
 . . .
vowels.add('a');
vowels.add('A');
 . . .
if (vowels.contains(myString.charAt(i))) ...

You can also dump the contents of a String into a char[] with a String class method, and iterate that.