Java 7 for Absolute Beginners

C H A P T E R 5

77

Control Flow, Looping, and

Branching

Control flow, looping, and branching are fundamental concepts in all programming. Control flow

consists of running different code under different conditions. Looping consists of running the same code

(though often with different values or different objects each time) until some condition has been met.

Branching consists of doing something else when some condition has been detected. The thread that

ties them all together is detecting conditions.

Control Flow

Java offers two constructs for controlling the flow of a program.

• if and if-else


• switch

■ Note try-catch blocks offer a form of control flow, because you can try something and then do something else

if the first thing you tried throws an exception. However, because that mechanism relies on catching exceptions,

it's not really a control flow mechanism. Because exceptions happen only when something goes wrong, they

shouldn't be thought of (and certainly shouldn't be used for) branching.

if and if-else Statements

You've already seen some examples of if statements, but let's examine another. Let's start with a sample

that's about as simple as it can be, as shown in Listing 5-1.

Java 7 for Absolute Beginners

© Jay Bryant 2012

J. Bryant,