READING
CHAPTER 9
SECTION 2
"Strings"

- string
  - sequence of characters that is treated as a single value
  - represented in Java with the String class
- charAt method
  - takes an integer
  - returns the character at that position in the string
- 0-based indexing
- length method
- last character is length - 1
- String is an object, so String variables are references
- value of a variable X is a reference to an object of class Y
  - X is a Y object
  - X is an instance of Y
- create a new String instance using the method new
- String is the only class that allows primitive-style shorthand for creating new instances
- toUpperCase method
  - String instance method
  - returns a new String which is the original String in all upper case
  - does not alter the original String
- out-of-bound exception
  - use short-circuit evaluation to avoid
- equals method
- equalsIgnoreCase method
- compareTo method
  - instance method
  - takes another String as an argument
  - returns an integer: 0 if they are equal, a negative number if str1 < str2, and a positive number if str1 > str2
  - exact numerical value determined by Unicode lexicographic value
- substring method
  - takes two integer arguments: beginIndex and endIndex
  - returns the piece of the String including the beginIndex, but excluding the endIndex

Quick Check
1. a. Porm
   b. Morld Mide Meb
2. String str = ...
   for (int i = str.length() - 1; str >= 0; str--) {
       System.out.println(str.charAt(i));
   }
3. a. yes
   b. yes
   c. yes
   d. yes
   e. no, because "language" only has 8 characters, so we can only use charAt between 0 and 7
   f. yes
4. equals would say that "Red Sox" is not equal to "red sox", but equalsIgnoreCase would say they are equal