SELECTIONS - Introduction to Java Programming: Comprehensive Version - page 100

3.13 switch Statements
A switch statement executes statements based on the value of a variable or an
expression.

Key
Point

The if statement in Listing 3.5, ComputeTax.java, makes selections based on a single true
or false condition. There are four cases for computing taxes, which depend on the value of
status . To fully account for all the cases, nested if statements were used. Overuse of nested
if statements makes a program difficult to read. Java provides a switch statement to sim-
plify coding for multiple conditions. You can write the following switch statement to replace
the nested if statement in Listing 3.5:

switch (status) {
case 0 : compute tax for single filers;
break ;
case 1 : compute tax for married jointly or qualifying widow(er);
break ;
case 2 : compute tax for married filing separately;
break ;
case 3 : compute tax for head of household;
break ;
default : System.out.println( "Error: invalid status" );
System.exit( 1 );
}

The flowchart of the preceding switch statement is shown in Figure 3.5.

status is 0

Compute tax for single filers break

status is 1

Compute tax for married jointly or qualifying widow(er) break

status is 2

Compute tax for married filing separately break

status is 3

Compute tax for head of household break

default

Default actions

F IGURE 3.5

The switch statement checks all cases and executes the statements in the
matched case.

This statement checks to see whether the status matches the value 0 , 1 , 2 , or 3 , in that
order. If matched, the corresponding tax is computed; if not matched, a message is displayed.
Here is the full syntax for the switch statement: switch statement

switch ( switch -expression) {
case value1: statement(s)1;
break ;