SELECTIONS - Introduction to Java Programming - page 91

3.6

Write an if statement that increases pay by 3% if score is greater than 90 , other-
wise increases pay by 1%.

✓ ✓

Check

Point

3.7

What is the printout of the code in (a) and (b) if number is 30 ? What if number
is 35 ?

if (number % 2 == 0 )
System.out.println(number + " is even." );

if (number % 2 == 0 )
System.out.println(number + " is even." );
else
System.out.println(number + " is odd." ); System.out.println(number + " is odd." );

(a) (b)

3.6 Nested if and Multi-Way if-else Statements
An if statement can be inside another if statement to form a nested if statement.

Key
Point

The statement in an if or if-else statement can be any legal Java statement, including
another if or if-else statement. The inner if statement is said to be nested inside the outer
if statement. The inner if statement can contain another if statement; in fact, there is no
limit to the depth of the nesting. For example, the following is a nested if statement:

nested if statement

if (i > k) {
if (j > k)
System.out.println( "i and j are greater than k" );

}
else
System.out.println( "i is less than or equal to k" );

The if (j > k) statement is nested inside the if (i > k) statement.
The nested if statement can be used to implement multiple alternatives. The statement
given in Figure 3.4a, for instance, assigns a letter grade to the variable grade according to the
score, with multiple alternatives.

if (score >= 90.0 )
grade = 'A' ;
else
if (score >= 80.0 )
grade = 'B' ;
else
if (score >= 70.0 )
grade = 'C' ;
else
if (score >= 60.0 )
grade = 'D' ;
else
grade = 'F' ;

if (score >= 90.0 )
grade = 'A' ;
else if (score >= 80.0 )
grade = 'B' ;
else if (score >= 70.0 )
grade = 'C' ;
else if (score >= 60.0 )
grade = 'D' ;
else
grade = 'F' ;

Equivalent

This is better

(a) (b)
A preferred format for multiple alternatives is shown in (b) using a multi-way
if-else statement.

F IGURE 3.4

The execution of this if statement proceeds as shown in Figure 3.5. The first condition
(score >= 90.0) is tested. If it is true , the grade becomes A . If it is false , the second
condition (score >= 80.0) is tested. If the second condition is true , the grade becomes B .
If that condition is false , the third condition and the rest of the conditions (if necessary)
are tested until a condition is met or all of the conditions prove to be false . If all of the
conditions are false , the grade becomes F . Note that a condition is tested only when all of
the conditions that come before it are false .