Thread: Why do I get an exception in this simple loop?

Hey there guys. I'm new to loops and I'm trying to write a simple code that outputs the number of uppercase letters in a string. However, I get an exception when I run the code. What's wrong? Here is the code:

public class CountingMatches 
{
	public static void main(String[] args)
	{
		String str = "Hello, World!";
 
		int upperCaseLetters = 0;
		for (int i = 0; i <= str.length(); i++)
		{
			char ch = str.charAt(i);
			if(Character.isUpperCase(ch));
			{
				upperCaseLetters++;
			}
		}
 
		System.out.println(upperCaseLetters);
	}
 
}

And this is the exception I get:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 13
at java.lang.String.charAt(Unknown Source)
at CountingMatches.main(CountingMatches.java:11)

Thanks.

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


str.length is = the index number of the last element + 1

Like jps said, you're taking the number of the last element in your string, and adding 1 to it. You can solve this by simply saying either:

for(int i = 0; i <= str.length() - 1; i++)

or the one I think is better

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