Chapter 3
lazy operator
&& and ||
short-circuit operator
&& and ||
Write an expression that returns a random integers between 0 and 9, inclusive.
(int)(Math.random() * 10)
fall-through behavior
. Once a case is matched, the statements starting from the matched case are executed until a break statement or the end of the switch statement is reached
What is (int)Math.random() * 10?
0
Assume age = 16; ticketPrice = age >= 16 ? 20 : 10; What is ticketPrice?
20
Boolean expression
A Boolean expression is an expression that evaluates to a Boolean value: true or false . We now introduce Boolean types and relational operators.
Boolean value
A Boolean expression is an expression that evaluates to a Boolean value: true or false . We now introduce Boolean types and relational operators.
Assume x is an integer. Write a simple expression that returns true if x is even or false if x is odd.
Assume x is an integer. Write a simple expression that returns true if x is even or false if x is odd.
dangling else ambiguity
However, the else clause actually matches the second if clause. This situation is known as the dangling else ambiguity.
operator associativity
If operators with the same precedence are next to each other, their associativity determines the order of evaluation. All binary operators except assignment operators are left associative. For example, since + and - are of the same precedence and are left associative, the expression
debugging
Logic errors are called bugs. The process of finding and correcting errors is called debugging.
boolean data type
The boolean data type declares a variable with the value either true or false.
conditional operator
The symbols ? and : appear together in a conditional expression. They form a conditional operator and also called a ternary operator because it uses three operands. It is the only ternary operator in Java.
What is !true?
false
What is false || false?
false
What is true && false?
false
flowchart
is a diagram that describes an algorithm or process, showing the steps as boxes of various kinds, and their order by connecting these with arrows.
What is !false?
true
What is true && true?
true
What is true || false?
true
selection statement
used for programming with alternative courses of actions. There are several types of selection statements: one-way if statements, two-way if-else statements, nested if statements, multi-way if-else statements, switch statements, and conditional expressions.