If you're seeing this message, it means we're having trouble loading external resources on our website.
If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.
To log in and use all the features of Khan Academy, please enable JavaScript in your browser.
for (int i = 0; i < str.length; i++) {
String letter = str.substring(i, i+1);
System.out.println(letter.toUpperCase());
}
