CODEWITHSUNDEEP
java
Thomas P
Thomas P

Reputation: 27

I keep getting a java.lang.StringIndexOutOfBoundsException

I am trying to get the user to insert a string of at least 3 characters and if its even the program prints the first half, and if it is odd the program prints the middle 3. I keep receiving this error when I put in anything more than 3 characters. 

import java.util.Scanner;

public class Stringex {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);

System.out.print("Please enter a string at least 3 characters long ");
String a = input.nextLine();


int numberofletters = a.length();

if (numberofletters < 3) {
    System.out.print("Sorry the string you entered is not long enough");
}
else if (numberofletters%2 == 0) {
    System.out.print(a.substring(0, numberofletters/2));
}
else {
    System.out.print(a.substring(numberofletters/2 - 1, numberofletters +2 ));
}


}

}

Upvotes: 0

Views: 63

Answers (1)

ASutherland
ASutherland

Reputation: 77

As mentioned in a comment your issue is with this statement:

else {
    System.out.print(a.substring(numberofletters/2 - 1, numberofletters +2 ));
}

Looking at the documentation for subString you can see the issue is with the endIndex you are passing in. Since numberofletters refers to the length of your string, adding 2 to it will always index past the end of the string.

The documentation also helpfully shows what exceptions subString can throw and in what circumstance :

Throws: IndexOutOfBoundsException - if the beginIndex is negative, or endIndex is larger than the length of this String object, or beginIndex is larger than endIndex.

[Emphasis mine]

Upvotes: 2

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