Deck 10: Javascript: Arrays

Question 1

_________ are data structures consisting of related data items (sometimes called collections of data items).

A) lvalues
B) composites
C) arrays
D) variables

Answer 1

C

Question 2

What is the effect of the join statement in the following code
Var theArray1 = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
Var theArray2 = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
Var value = theArray1.join( " " );

A) The join method will concatenate the values of theArray2 to theArray1.
B) The join method will concatenate the values of theArray1 to theArray2.
C) The join method will create a string from the values in theArray1.
D) The join method will create a string with the values of theArray2 concatenated to the values of theArray1.

Answer 2

C

Question 3

What does the following code do
For ( var col = 0; col < a[ 2 ].length; ++col )
A[ 2 ][ col ] = 0;

A) Sets the rows and columns to zero.
B) Sets the rows to zero.
C) Sets the columns to zero.
D) Sets all the elements in row 2 to zero.

Answer 3

D

Question 4

Which of the following is an illegal array initialization statement

A) var n = [ 10, 20, 30, 40, 50 ];
B) var n = new Array( 10, 20, 30, 40, 50 );
C) var n[ 10, 20, 30, 40, 50 ];
D) var n = new Array( 5 ); for ( var i = 1; i < = 5; i++ )
N[ i ] = i * 10 ;

Question 5

What will the browser display if the following script is executed
< script type = "text/javascript" >
< !--
Var theArray = [ 1, 2, 3, 4, 5, 6, 7, 8, 9 ];
ModifyArray( theArray[ 3 ] );
Document.write( theArray.join( " " ) );
Function modifyArray( i )
{
I = 11;
}
//-- >
< /script >

A) Nothing, the browser will generate an error.
B) 1 2 3 4 5 6 7 8 9
C) 1 2 11 4 5 6 7 8 9
D) 1 2 3 11 5 6 7 8 9

Question 6

To refer to a particular location or element in the array, we spec ify the name of the array and the ________ of the particular element in the array.

A) contents
B) size
C) position number
D) type

Question 7

Which of the following is the proper method to access the length of the array arr

A) arr[].length
B) arr[subscript].length
C) arr.length
D) arr(length)

Question 8

In JavaScript, numbers and boolean values are passed to functions by ________.

A) value
B) parameters
C) memory
D) reference

Question 9

What is the value of num assuming that all 12 elements of array test are initialized to 3
++test[ 7 ];
Var num = test[ 7 ];

A) 3
B) 4
C) 8
D) 10

Question 10

The first statement below ________ the array while the second statement ________ the array.
Var c;
C = new Array( 12 );

A) declares, initializes
B) initializes, declares
C) declares, allocates
D) allocates, declares

Question 11

Pass-by- ________ is the method of passing the argument's address in memory to a function.

A) value
B) parameters
C) memory
D) reference

Question 12

By default, the JavaScript sort method uses ________ to sort the array passed to it.

A) string comparison
B) binary search
C) linear search
D) bubble sort

Question 13

The sort method can be given a function to use for the comparisons it makes, called a(n) ________ function.

A) isLessThan
B) compare
C) compareTo
D) comparator

Question 14

When working with data stored in arrays, it's often necessary to determine whether an array contains a value that matches a certain ________.

A) search value
B) value index
C) sub initializer
D) key value

Question 15

Pass-by- ________ is the method of passing a copy of the argument's value to a function.

A) value
B) parameters
C) memory
D) reference

Question 16

What would the browser output if the following script is executed
< script type = "text/javascript" >
< !--
Var array = [ [ 1, 2, 3 ], [ 1, 2, 3 ] ];
For ( var i in array )
{
For ( var j in array[ i ] )
Document.write( array[ i ][ j ] + " " );
Document.writeln("< br / >");
}
//-- >
< /script >

A) Nothing, the script would generate an error
B) 1 2 3
C) 1 2 3 4 5 6
D) 1 2 3 1 2 3

Question 17

Which of the following is the proper method to dynamically allocate memory to an array of 100 elements

A) var c = new c[ 100 ];
B) var c = new c( 100 );
C) var c = new Array[ 100 ];
D) var c = new Array( 100 );

Question 18

In JavaScript, all objects and arrays are passed to functions by ________.

A) value
B) parameters
C) memory
D) reference