Cmsc 104 Exam 4

Front 1

switch is a legal identifier in JavaScript.

Back 1

False

Front 2

count++; is equivalent to count = count + 1;

Back 2

True

Front 3

Every function must have a return statement.

Back 3

False

Front 4

In JavaScript, the function keyword is used to define a function.

Back 4

True

Front 5

When a function is called, its local variables initially contain the value 0.

Back 5

False

Front 6

Actual and formal function parameters must have the same name.

Back 6

False

Front 7

A function always returns the value 0.

Back 7

False

Front 8

When a function is called, the number of arguments passed should match the number of formal parameters.

Back 8

True

Front 9

After a function has returned, the values stored in its local variables are copied into variables in the calling function that have the same name.

Back 9

False

Front 10

The values stored in the local variables of a function are not saved when the function exits.

Back 10

True

Front 11

Formal parameters must also be declared inside of a function using the var keyword.

Back 11

False

Front 12

JavaScript is an interpreted language.

Back 12

True

Front 13

If the variables a and b are holding the values 0 and 1, respectively, what is the value of the following expression : ( a || b ) ?

Back 13

True

Front 14

If the variables a and b are holding the values 0 and 1, respectively, what is the value of the following expression : ( a && b ) ?

Back 14

False

Front 15

If the variables a and b are holding the values 1 and 2, respectively, what is the value of the following expression : ( a + b ) ?

Back 15

True

Front 16

If the variables a and b are holding the values 0 and 6, respectively, after the statement a += b the new values of a and b are both 6.

Back 16

False

Front 17

All array elements are initialized to 0 when the array is created.

Back 17

False

Front 18

The default case is required in the switch selection structure.

Back 18

False

Front 19

The default case must be the last case in the switch selection structure.

Back 19

False

Front 20

The break statement is required in the default case of the switch selection structure.

Back 20

False

Front 21

An array is used store a list of items.

Back 21

True

Front 22

Array subscripts must always start at 0.

Back 22

True

Front 23

The function keyword is used when making a function call.

Back 23

False

Front 24

The fourth element of an array named bob is bob[4]

Back 24

False

Front 25

Arrays must always be initialized using a for loop.

Back 25

False

Front 26

Given the function call,
PrintGreeting();
how many arguments does the function have?

Back 26

0

Front 27

The function header comment

Back 27

[b.] gives information about the function to the person reading the code.

Front 28

What is the output of the following code fragment?
var a = 3, b = 17 ;

a = b % a ;
b++ ;
alert("a = " + a + ", b = " + b);

Back 28

[d.] a = 2, b = 18

Front 29

The output of the following program fragment is:
test = 1 ;
if (test = 2) {
alert("Beam down the landing party.\n") ;
} else if (test == 1) {
alert("Jim, he's dead.\n") ;
} else if (test == 0) {
alert("Scotty, four to beam up.\n") ;

Back 29

[a.] Beam down the landing party.

Front 30

Which of the following statements will print out the variable x with exactly 1 decimal place, e.g. 123.4

Back 30

[a.] alert (x.toFixed(1));

Front 31

A single JavaScript statement that decrements the value of x, giving x a new value is

Back 31

[a.] x--;

Front 32

How many arguments does the following function call have?
ave = FindAverage(num1, num1);

Back 32

2

Front 33

How many arguments does the following function call have?
PrintMessage("Hello there!");

Back 33

1

Front 34

Which of the following is a function header for a function that has only 1 parameter?

Back 34

[b.] function AddOne(num1)

Front 35

What is the index of the last element in an array of size 10?

Back 35

[c.] 9

Front 36

The character used to display a newline in an alert statement is

Back 36

[a.] \n

Front 37

The tag used to display a newline in a document.write() statement is

Back 37

[d.] <br />

Front 38

Which operator can be used on strings and numbers?

Back 38

[b.] +

Front 39

How can you increment the variable num by 1?

Back 39

[a.] num++
[b.] num = num + 1
[c.] num += 1

Front 40

When a variable is declared, what is its initial value?

Back 40

NULL (aka empty)

Front 41

Explain why it is sometimes necessary to use parseInt() or parseFloat() after a call to prompt().

Back 41

Because the prompt command doesn't know if it is capturing a string or a number

Front 42

Briefly describe one reason to write your own functions.

Back 42

It keeps you from having to write the same code over and over again

Front 43

Write a function called SumTwo that returns the sum of two numbers, where the numbers, num1 and num2 are passed to it.

Back 43

function SumTwo(num1, num2) {
return parseInt(num1) + parseInt(num2);
}

Front 44

Name two benefits of using constants in a program.

Back 44

You can't accidentally change the value of a constant. Constants make a program easier to modify

Front 45

Write a function called Smallest that takes three arguments, x, y and z and returns the smallest of the three arguments. You can assume x, y and z are numbers.

Back 45

function Smallest(x,y,z) {
var smallest = z;
if (y < smallest) {
smallest = y;
}
if (x < smallest) {
smallest = x;
}
return smallest;

Front 46

What is the starting index of an array?

Back 46

0

Front 47

Briefly describe why the function definitions are placed in the <head> section of the document.

Back 47

It is easier to organize and understand the program

Front 48

Write a function called AlertEven that takes 1 argument, n, and alerts whether the value is even or not. The function should not return anything. For example if n is 6, the output would be "6 is even". If n is 7, the output would be "7 is not even".

Back 48

function AlertEven(n) {
if (n % 2 == 0) {
alert("even");
} else {
alert("odd");
}
}

Front 49

In an array declared with n elements, what is the index of the last element ?

Back 49

n-1 because the first element of the array is index 0 (e.g. myarray[0] )

Front 50

Write the statements that would declare a 10-element array and initialize all of its elements to 1.

Back 50

var myarray = new Array(10);
myarray=1;

Front 51

Write a function called Average that takes three number parameters n1, n2, and n3 and returns the value of the average of the three.

Back 51

function Average(n1, n2, n3) {
return ((n1 + n2 + n3) / 3);
}

Front 52

Write a function called SumN that takes one parameter, n, and returns the sum of the integers from 1 to n.

Back 52

function SumN(n) {
var sum = 0;
var i;
for (i=1;i<=n;i++) {
sum = sum + i;
}
return sum;
}

Front 53

Write a function called FeetToInches that takes numFeet as an argument and returns the number of inches in that many feet.

Back 53

function FeetToInches(numFeet) {
return (numFeet * 12);
}

Front 54

Write a function called PrintBox that will print a rectangle made up of any character passed to it. Here is the function header:
function PrintBox (rows, columns, ch)
This call to PrintBox,
PrintBox(3, 10, "$");

should print:
$$$$$$$$$$
$$$$$$$$$$
$$$$$$$$$$

Back 54

function PrintBox(rows, columns, ch) {
var i;
var j;
for(i=1;i<=rows;i++) {
for(j=1;j<=rows;j++) {
document.write(ch);
}
}
}

Front 55

Write a set of one or more statements that will print out one of the brief messages given in the table below, depending on a person's grade point average. Assume that the grade point average has already been read into a variable called gpa. Include code to print a warning message if the value of gpa is not in the range 0.0 to 4.0. You should decide which control structure (if, if-else, switch, etc...) is appropriate.
GPA range Student Rating
3.50 - 4.0 Dean's list
2.0 - 3.49 Satisfactory
1.0 - 1.99 Probation
0.0 - 0.99 Suspended

Back 55

if (gpa < 0 || gpa > 4) {
alert("gpa is not correct");
} else {

document.write("<b>GPA range &nbsp;&nbsp;&nbsp; Student Rating");
if (gpa >= 3.50) {
document.write("3.50-4.0 &nbsp;&nbsp;&nbsp; Dean's List");
} else if (gpa >= 2.0) {
document.write("2.0-3.49 &nbsp;&nbsp;&nbsp; Satisfactory");
} else if (gpa >= 1.0) {
document.write("1.0 - 1.99 &nbsp;&nbsp;&nbsp; Probation");
} else {
document.write("0.0 - 0.99 &nbsp;&nbsp;&nbsp; Suspended");
}
}

Front 56

Given an array of size 100 called numbers, write a code segment that would find the average of the array elements. You can assume that the array has already been initialized to hold values.

Back 56

var sum = 0;
var i;
for (i=1;i<=99;i++){
sum=sum+numbers(i);
}
alert("Average is " + (sum / 100));

Front 57

Given an array of size 100 called numbers, write a code segment that would find the smallest element in the array. You can assume that the array has already been initialized to hold values.

Back 57

var smallest=numbers(0);
var i;
for(i=1;i<=99;i++){
if (numbers(i) < smallest) {
smallest = numbers(i);
}
}
alert("Smallest is " + smallest);

Front 58

Given an array of size 100 called numbers, write a code segment that would find the largest element in the array. You can assume that the array has already been initialized to hold values.

Back 58

var largest=numbers(0);
var i;
for(i=1;i<=99;i++){
if (numbers(i) > largest) {
largest = numbers(i);
}
}
alert("Largest is " + largest);

Front 59

What is wrong with the following code segment? Modify the code so it works correctly.

var i = 1;

//this while loop displays the numbers 1-10
while (i <= 10)
{
alert("i is " + i);
i--;
}

Back 59

var largest=numbers(0);
var i;
for(i=1;i<=99;i++){
if (numbers(i) > largest) {
largest = numbers(i);
}
}
alert("Largest is " + largest);

Front 60

Give a description of a problem/program where you would use an array and explain why you would choose to use an array. What would the alternative to an array be?

Back 60

Change the "i--" to "i++"

Front 61

alert ("JavaScript\nis\nfun.");

Back 61

Output:

JavaScript
is
fun.

Front 62

var a = 2, b = 3;

b = b * a;
b++;
a += b;
alert (a + " " + b);

Back 62

Output:

"9 7"

Front 63

var a = 5, b = 4;

b += a;
b++;
a = a - b;
document.write (a + " " + b);

Back 63

Output:

"5 10"

Front 64

var n = 1234;

while (n > 0)
{
document.write(n + "<br />");
n = n / 10;
n = Math.floor(n);
}
/* Hint: The Math.floor() function truncates a number
downwards to the nearest integer. For example,
the floor of 34.5 would be 34 */

Back 64

Output:

1234
123
12
1

Front 65

var m;

for (m = 1; m <= 5; m++)
{
switch (m)
{
case 1:
document.write ("one");
break;
case 2:
document.write ("two");
break;
case 3:
document.write ("three");
break;
default:
document.write ("Default case");
}
document.write ("<br />");
}

Back 65

Output:

one
two
three
Default case
Default case

Front 66

var x;

for (x = 4; x >= 0; x--)
{
switch (x)
{
case 3:
document.write ("tres");
break;
case 2:
document.write ("dos");
break;
case 1:
document.write ("uno");
break;
default:
document.write ("Default case");
}
document.write ("<br />");
}

Back 66

Output:

Default case
tres
dos
uno
Default case

Front 67

<head>
<script type="text/javascript">
<!--
function X (m)
{
document.write("In function X: " + m + "<br />");
return (m + 2);
}
//-->
</script>
</head>
<body>
<script type="text/javascript">
<!--
var m;

m = X(5);
document.write("After the call to function X: " + m);
//-->
</script>

Back 67

Output:

In function X:5
After the call to function X: 7

Front 68

<head>
<script type="text/javascript">
<!--
function Foo (num)
{
num++;
document.write("In function Foo: " + num + "<br />");
return num;
}
//-->
</script>
</head>
<body>
<script type="text/javascript">
<!--
var num = 7;

Foo(num);
document.write("After the call to function Foo: " + num);
//-->
</script>

Back 68

Output:

In function Foo:8
After the call to function Foo:8