Answers to Self-Review Exercises (Sections C.14–C.20)

C.8

a) for, while.

b) after.

c) switch.

d) continue.

e) && (conditional AND).

f) false.

C.9

a) False. The default case is optional. If no default action is needed, then there’s no need for a default case.

b) False. The break statement is used to exit the switch statement. The break statement is not required for the last case in a switch statement.

c) False. Both of the relational expressions must be true for the entire expression to be true when using the && operator.

d) True.

e) True.

C.10

a)

Click here to view code image

sum = 0;
for ( count = 1; count <= 99; count += 2 )
   sum += count;

b) double result = Math.pow( 2 . 5 , 3 );

c) i = 1 ;

while ( i <= 20 )
{
   System.out.print( i );

   if ( i % 5 == 0 )
      System.out.println();
   else
      System.out.print( ' ' );

   ++i;
}

d)

for ( i = 1; i <= 20; ++i )
{
   System.out.print( i );

   if ( i % 5 == 0 )
      System.out.println();
   else
      System.out.print( ' ' );
}

C.11

a) Error: The semicolon after the while header causes an infinite loop, and there’s a missing left brace.

Correction: Replace the semicolon by a {, or remove both the ; and the }.

b) Error: Using a floating-point number to control a for statement may not work, because floating-point numbers are represented only approximately by most computers.

Correction: Use an integer, and perform the proper calculation in order to get the values you desire:

Click here to view code image

for ( k = 1; k != 10; ++k )
   System.out.println( (double) k / 10 );

c) Error: The missing code is the break statement in the statements for the first case.

Correction: Add a break statement at the end of the statements for the first case. This omission is not necessarily an error if you want the statement of case 2: to execute every time the case 1: statement executes.

d) Error: An improper relational operator is used in the while’s continuation condition.

Correction: Use <= rather than <, or change 10 to 11.