CODEWITHSUNDEEP
java
Michele Rosito
Michele Rosito

Reputation: 13

StringIndexOutOfBoundsException: string index out of range

I can't find an answer about this exception. THe program is very simple but, i don't know why is incorrect.

/**
 * Program selects the first word from the sentence "Hello, my dear!" with
 * the String Classes's methods this.indexOf() and this.substring()  
 * 
 *
 * Last modify: 29th October 2015
 */

public class TakeSubstringWanted {

    public static void main(String[] args) {

        String sentence = "Hello, my dear!";
        String reference = "Hello";

        System.out.println("The sentence is: " + sentence);
        System.out.println("You want to take the first word of that sentence");
        System.out.println("Give me a second...");

        int firstReference = sentence.indexOf(reference);
        int firstLength = reference.length();
        System.out.println("The first reference of the searched word is " + firstReference);
        System.out.println("The first word of the sentence " + sentence + " is: " + "\"" + sentence.substring(firstReference, firstLength) + "\"");
        int secondReference = sentence.indexOf("my");
        System.out.println("The second reference of the searched word is " + secondReference);
        int secondLength = "my".length();
        System.out.println(secondLength);
        System.out.println(sentence);
        System.out.println("The second word of the sentence " + sentence + " is: " + "\"" + sentence.substring(secondReference, secondLength) + "\"");
    }

}

Upvotes: 0

Views: 349

Answers (6)

Shivam
Shivam

Reputation: 649

Instead of giving the length, you have to give the end index. The substring method works like:

substring(int beginIndex, int endIndex)

Change

int firstLength = reference.length();
int secondLength = "my".length();

to

int firstLength = sentence.indexOf(",");
int secondLength = sentence.indexOf(" dear");

Try this:

String sentence = "Hello, my dear!";
String reference = "Hello";

System.out.println("The sentence is: " + sentence);
System.out.println("You want to take the first word of that sentence");
System.out.println("Give me a second...");

int firstReference = sentence.indexOf(reference);
int firstLength = sentence.indexOf(",");

System.out.println("The first reference of the searched word is " + firstReference);
System.out.println("The first word of the sentence " + sentence + " is: " + "\"" + sentence.substring(firstReference, firstLength) + "\"");

int secondReference = sentence.indexOf("my");

System.out.println("The second reference of the searched word is " + secondReference);

int secondLength = sentence.indexOf(" dear");

System.out.println(secondLength);
System.out.println(sentence);
System.out.println("The second word of the sentence " + sentence + " is: " + "\"" + sentence.substring(secondReference, secondLength) + "\"");

Upvotes: -1

Sourav Jena
Sourav Jena

Reputation: 1

when you are using sentence.substring() for second time the second parameter of substring method should be greater than first parameter..in your case the first parameter is 7 and second parameter is 2 ...thats why you are getting String index out of range: -5

Upvotes: 0

Andy Turner
Andy Turner

Reputation: 140534

The second parameter of substring is the end index, not the number of characters to take.

sentence.substring(secondReference, secondLength)

When you run this, secondLength is 2 (the length of "my"), but secondReference is 7, greater than 2, resulting in such an exception.

If you want those two characters, you'd need to use:

sentence.substring(secondReference, secondLength+secondReference)

Upvotes: 0

Felix Gerber
Felix Gerber

Reputation: 1651

Your Problem is here:

sentence.substring(secondReference, secondLength)

Your giving to lengths but it should be 

sentence.substring(startIndex, endIndex);

Hope that helps!

Upvotes: 0

Ori Lentz
Ori Lentz

Reputation: 3688

Your problem is in the last line:

System.out.println("The second word of the sentence " + sentence + " is: "
             + "\"" + sentence.substring(secondReference, secondLength) + "\"");

because your secondReference = 7 and secondLength = 2, however if you look at the documentation for substring method:

public String substring(int beginIndex, int endIndex)

Returns a new string that is a substring of this string. The substring begins at the specified beginIndex and extends to the character at index endIndex - 1. Thus the length of the substring is endIndex-beginIndex.

...

Throws: IndexOutOfBoundsException - if beginIndex or endIndex are negative, if endIndex is greater than length(), or if beginIndex is greater than startIndex

Meaning, you're asking substring to return a string from index 7 to index 2, which causes an IndexOutOfBoundsException. What you probably meant to do was:

sentence.substring(secondReference, secondReference + secondLength)

Upvotes: 3

Emerson Cod
Emerson Cod

Reputation: 2100

your last substring starts at pos 7 and the end index is 2, which is not possible. The last index is the end index, not the length of the char you like to take 

sentence.substring(secondReference, seconfReference+secondLength);

would it be then

Upvotes: 0

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