Loops and Logic - Beginning Java - page 93

You have four if statements altogether. The first if tests whether symbol is ' A ' or greater. If it is, it could
be a capital letter, a small letter, or possibly something else. But if it isn't, it is not a letter at all, so the
else for this if statement (toward the end of the program) produces a message to that effect.
The nested if statement, which is executed if symbol is ' A ' or greater, tests whether it is ' Z ' or less. If
it is, then symbol definitely contains a capital letter, and the appropriate message is displayed. If it isn't
then it may be a small letter, so another if statement is nested within the else clause of the first nested
if to test for this possibility.
The if statement in the else clause tests for symbol being greater than ' a '. If it isn't, you know that
symbol is not a letter, and a message is displayed. If it is, another if checks whether symbol is ' z ' or
less. If it is you have a small letter, and if not you don't have a letter at all.
You have to run the example a few times to get all the possible messages to come up. They all will —
eventually.
After having carefully crafted our convoluted and cumbersome condition checking, I can now reveal that
there is a much easier way to achieve the same result. You'll see that in the section “Logical Operators”
that follows immediately after a brief word on working with enumeration values.
Comparing Enumeration Values
You can't compare variables of an enumeration type using the comparison operators but you can compare
them using a method that every enumeration object provides. Suppose you define an enumeration type as:
enum Season { spring, summer, fall, winter }
You can now define and initialize a variable of type Season with the following statement:
Season season = Season.summer;
If you later want to check what the season variable currently holds, you could write:
if(season.equals(Season.spring)) {
System.out.println("Spring has sprung, the grass is riz.");