Directing Program Flow - JAVA Programming for Engineers - page 88

The case constant does not require tic marks when the control state-
ment evaluates to an int type. The following code fragment shows a case
construct in which the switch variable is of type int.

int intVar;
...
switch (intVar)
{

case 1:
System.out.println("Input was 1");
break;
case 2:
System.out.println("Input was 2");
break;9

...
}

The break keyword is optional, but if it is not present at the end of a
case block, then the following case or default blocks execute. In other
words, execution in a switch construct continues until a break keyword
or the end of the construct is encountered. When a break keyword is en-
countered, execution is immediately directed to the end of the switch
construct. A break statement is not required on the last block (case or de-
fault statement), although the break is usually included to make the code
easier to read.

The blocks of execution within a switch construct are enclosed in ros-
ters; however, the case and the default keywords automatically block the
statements that follow. Rosters are not necessary to indicate the
first-level execution block within a case or default statement.

The following program shows the processing necessary for implement-
ing menu selection using a Java switch construct.

On the Web

The MenuDemo.java program is found in the Chapter 9 folder at
www.crcpress.com .

// File name: MenuDemo.java

// Reference: Chapter 9

//
// Java program to demonstrate menu selection

// Topics:

// 1. Using the switch construct

//
// Requires:

// 1. Keyin class in the current directory