String Index out of bounds error, basic program

Question

This program does what I want it to do but it also outputting a massive big error. Which says something like "array out of bounds. string index out of bounds". The program is meant to take an input of a sentence and rewrite it using different letters (4 characters up) from the alphabet. Please help me clear up this error!

public class Encryption
{
public static void main (String [] args)
{
System.out.print("Enter a message to encrypt: ");
String input = Console.readString();

for(int i = 0; i<100; i++)
{
char oldChar = input.charAt(i);

char encryptedChar = (char) (oldChar + 4);

System.out.print(encryptedChar);
}   
}

What part of the error don't you understand? Hint: When should your loop stop? — SLaks
– SLaks, Commented Dec 3, 2013 at 19:42

rgettman · Accepted Answer · 2013-12-03 19:42:59Z

1

If you get a StringIndexOutOfBoundsException, then your input isn't 100 characters long.

Don't expect 100 characters; stop your for loop when i reaches your string's length.

for (int i = 0; i < input.length(); i++)

answered Dec 3, 2013 at 19:42

rgettman

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Comments

Arpit · Accepted Answer · 2013-12-03 19:43:28Z

1

Is the input always a 100 character string, I believe not and that's the error. Replace 100 with input.length()

answered Dec 3, 2013 at 19:43

Arpit

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Comments

John Kugelman · Accepted Answer · 2013-12-03 19:43:05Z

0

Change your loop bounds. You're looping from i=0 to i=99 which will exceed the input length if the user types less than 100 characters.

for (int i = 0; i < input.length(); i++)

answered Dec 3, 2013 at 19:43

John Kugelman

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ou_joshua · Accepted Answer · 2013-12-03 19:44:11Z

0

As previously stated you hard coded the loop to iterate 100 chars. What if the string isn't 100 char

answered Dec 3, 2013 at 19:44

ou_joshua

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