Flow of Control - Absolute Java - page 120

The “or” Operator ||
You can form a more elaborate Boolean expression by combining two simpler Boolean
expressions using the “or” operator || .
SYNTAX (FOR A BOOLEAN EXPRESSION USING || )
( Boolean_Exp_1 ) || ( Boolean_Exp_2 )
EXAMPLE (WITHIN AN if-else STATEMENT)
if ((salary > expenses) || (savings > expenses))
System.out.println("Solvent");
else
System.out.println("Bankrupt");

If salary is greater than expenses or savings is greater than expenses (or both), then
the first System.out.println statement is executed; otherwise, the second System.
out.println statement is executed.

PITFALL: Strings of Inequalities

Do not use a string of inequalities such as min < result < max . If you do, your
program will produce a compiler error message. Instead, you must use two inequalities
connected with an && , as follows:

■

(min < result) && (result < max)

Self-Test Exercises

17. Write an if-else statement that outputs the word “Passed” provided the
value of the variable exam is greater than or equal to 60 and also the value
of the variable programsDone is greater than or equal to 10. Otherwise, the
if-else statement should output the word “Failed“. The variables exam and
programsDone are both of type int .
18. Write an if-else statement that outputs the word “Emergency” provided the value
of the variable pressure is greater than 100 or the value of the variable temperature
is greater than or equal to 212. Otherwise, the if-else statement should output
the word “OK“. The variables pressure and temperature are both of type int .

Evaluating Boolean Expressions
Boolean expressions are used to control branch and loop statements. However, a
Boolean expression has an independent identity apart from any branch statement or
loop statement you might use it in. A Boolean expression returns either true or false .