Chapter 8: JavaScript: Control Statements II

8.1 Which of the following is not required for counter-controlled repetition?

a) final value

b) initial value

c) sentinel

d) increment

c) sentinel

8.2 What should you use as a counter in counter-controlled repetition?

a) a floating-point number

b) a sentinel

c) an integer

d) a num object

c) an integer

8.3 What would the browser display if the following script were executed?

<script type = "text/javascript">
<!--
for ( var i = 0; var i < 5; var i++ )
document.write( "X" );
//-->
</script>

a) Nothing; the script would generate an error

b) XXXX

c) XXXXX

d) XXXXXX

a) Nothing; the script would generate an error

8.4 What would the browser display if the following script were executed?

<script type = "text/javascript">
<!--
for ( var i = 0; i < 5; i++ )
document.write( "O" );
//-->
</script>

a) Nothing; the script would generate an error

b) OOOO

c) OOOOO

d) OOOOOO

c) OOOOO

8.5 Which of the following is declared correctly and will not result in an error, assuming x = 2 and y = 30?

a) for ( var j = 10; j <= 80; j-- )

b) for ( var j = x, j <= y, j += 5 )

c) for ( var j = x; j <= 80 * y; j += 5 / x )

d) for ( var j = x; j <= 80 * y; j -= 5 )

c) for ( var j = x; j <= 80 * y; j += 5 / x )

8.6 What is the value of num after the following statement is performed?

num = 2 * Math.pow( 2, 3 );

a) 16

b) 18

c) 64

d) 8

a) 16

8.7 What is the value of num after the following statements are performed?

num = 2.4589;

num = num.toFixed( 2 );

a) 2

b) 2.46

c) 2.5

d) 2.45

b) 2.46

8.8 The ________ multiple-selection statement is used to handle decision making and can be used to replace multiple if and if...else statements.

a) do...while

b) case

c) break

d) switch

d) switch

8.9 switch statements contain ________ labels.

a) select

b) if...else

c) case

d) choice

c) case

8.10 In a switch statement, the ________ case clause is used to process exceptional conditions and is usually listed last.

a) break

b) default

c) else

d) then

b) default

8.11 Consider the following code selections. Assume count is initialized to 7 and num is initialized to 0.

i) ii)

do

{ while ( count < 6 )

num = count; num = count;

} while ( count < 6 )

What will the value of num be for i) and ii) respectively after the loops have been executed?

a) 0, 0

b) 0, 7

c) 7, 0

d) 7, 7

c) 7, 0

8.12 What would the browser display if it executed the following script?

<script type = "text/javascript">
<!--
var i = 0;

do
{
document.write( "O" );
i++;
} while ( i > 5 );

//-->
</script>

a) Nothing; the script would generate an error

b) O

c) OOOOO

d) OOOOOO

b) O

8.13 What would the browser display if it executed the following script?

<script type = "text/javascript">
<!--
for ( var count = 1; count <= 10; ++count )
{
if ( count == 5 )
break;
}

document.writeln( count );
//-->
</script>

a) Nothing; the script would generate an error.

b) 1

c) 5

d) 10

c

8.14 What would the browser display if it executed the following script?

<script type = "text/javascript">
<!--

for ( var count = 0; count < 10; ++count )
{
if ( count == 5 )
continue;
}

document.writeln( count );
//-->
</script>

a) Nothing; the script would generate an error.

b) 5

c) 9

d) 10

d) 10

8.15 Which of the following will not evaluate to true?

a) false || false

b) true || true

c) false || true

d) true || false

a) false || false

8.16 Which of the following will not evaluate to false?

a) false && false

b) true && true

c) false && true

d) true && false

b) true && true