Loops and Logic - Beginning Java - page 100

TABLE 3-3 : Methods Useful for Testing Characters
METHOD DESCRIPTION
isDigit() Returns the value true if the argument is a digit (0 to 9), and false otherwise.
isLetter() Returns the value true if the argument is a letter, and false otherwise.
isLetterOrDigit() Returns the value true if the argument is a letter or a digit, and false otherwise.
isWhitespace() Returns the value true if the argument is whitespace, which is any one of the follow-

ing characters:
space ( ' ' )
tab ( '\t' )
newline ( '\n' )
carriage return ( '\r' )
form feed ( '\f' )The method returns false otherwise.

You can find information on other methods in the Character class in the JDK documentation for the
class.

THE CONDITIONAL OPERATOR
The conditional operator is sometimes called a ternary operator because it involves three operands. It is
best understood by looking at an example. Suppose you have two variables of type int with the names
yourAge and myAge , and you want to assign the greater of the values stored in yourAge and myAge to a third
variable, older , which is also of type int . You can do this with the following statement:
older = yourAge > myAge ? yourAge : myAge;

The conditional operator has a logical expression as the first of its three operands — in this case, it is the
expression yourAge>myAge . If this expression is true , the operand that follows the ? symbol — in this case,
yourAge — is evaluated to produce the value resulting from the operation. If the expression yourAge>myAge
is false, the third operand that comes after the colon — in this case, myAge — is evaluated to produce the
value from the operation. Thus, the result of this conditional expression is yourAge , if yourAge is greater
than myAge , and myAge otherwise. This value is then stored in the variable older . The use of the conditional
operator in this assignment statement is equivalent to the if statement:
if(yourAge > myAge) {
older = yourAge;

} else {
older = myAge;

}

Remember, though, the conditional operator is an operator and not a statement, so you can use it in a
more complex expression involving other operators.
The conditional operator can be written generally as:
logical_expression ? expression1 : expression2