CMSC104 Spring 2010

Exam 2 Sample Questions

True/False Questions

Circle TRUE or FALSE for each of the following questions.

TRUE/FALSE
int is a reserved word in JavaScript.
TRUE/FALSE
2doList is a legal identifier in JavaScript.
TRUE/FALSE
JavaScript programs are interpreted in the browser.
TRUE/FALSE
If n is an integer, the value of the expression n % 5 is 0 whenever n is a multiple of 5.
TRUE/FALSE
If n is an integer, the value of the expression n % 7 is 0 whenever n is a not a multiple of 7.
TRUE/FALSE
If n is an integer, the value of the expression n % 6 is always less than 6.
TRUE/FALSE
In the JavaScript programing language, variable names can have at most 8 characters.
TRUE/FALSE
HTML is used to show the meaning of the text on a Web page.
TRUE/FALSE
CSS allows us to change the presentation of an HTML document.
TRUE/FALSE
What is the value of the expression 2 * 6 - 5 + 8 % 5
TRUE/FALSE
What is the value of the expression 3 * 5 - 19 + 7 % 4
TRUE/FALSE
What is the value of the expression 5 * 5 - 19 - 6 % 7
TRUE/FALSE
What is the value of the expression 3 * 5 - 12
TRUE/FALSE
The Internet and the WWW are interchangeable.
TRUE/FALSE
If the variables a and b are holding the values 5 and 2, respectively, the expression
a / b produces the result 2.5
TRUE/FALSE
A Web page is stored inside of the Web browser.
TRUE/FALSE
The CSS comment delimeters are /* and */.
TRUE/FALSE
Any code that can be written as a for loop can also be written as a while loop.
TRUE/FALSE
All variables should be declared and before they are used
TRUE/FALSE
<p>...</p> is an example of a self closing tag.
TRUE/FALSE
Each call to document.write() causes printing to start at the beginning of the next line.
TRUE/FALSE
JavaScript is a client-side scripting language.
TRUE/FALSE
Displaying text with an alert() has the same effect as displaying text with document.write().

A Feature of ...?

Identify each of the following as a feature of CSS, HTML, JavaScript or none

var
<head>
font-family
alert
text-align
!doctype
parseInt
document.write
RAM
</title>
/* */
if
default
color
for

Multiple Choice Questions

HTML stands for:
Which of the following denotes a comment in JavaScript?
What is the value of the expression 12 - 10 - 8 * 6 % 4 + 2 % 1
A valid sentinel value for a program getting grades as input would be
Execution of a break statement in the body of a while loop
Execution of a continue statement in the body of a for loop

Determine the output of the code fragment.

	var a = 5, b = 4, c = 1 ;
	
	if ( a < b + 1 ) {
	   alert("tea, earl grey, hot!");
	} else if ( a >= b + c ) {
	   alert("Ahead warp factor 9. Engage!");
	} else if ( a % b >= c ) {
	   alert("Warp core breach in 20 seconds!");
	} else {
	   alert("I sense a lot of anxiety in this room.");
	}

What is the effect of the following code?
```
	var i;
  
	for (i = 1 ; i <= 15 ; i = i + 1) 
	{
	   if ( i % 3 == 0) 
	   {
	      alert(i + " ");
           }
	}
```
The URL of a Web site is also called:
JavaScript and Java

Short Answers

Write a JavaScript code segment using a for loop that prints the numbers 1 to 10, inclusive, side-by-side on the same line with 1 space between each number
Write a JavaScript code segment using a while loop that prints the even numbers between 1 and 10, inclusive, side-by-side on the same line with 1 space between each number
Write a JavaScript code segment using a for loop that prints a 7 x 7 square out of asterisks.
Write a JavaScript code segment using a for loop that prints the following sequence of numbers: 3, 8, 13, 18, 23
Write a JavaScript code segment using a while loop that calculates and and prints the sum of the even integers from 2 to 30, inclusive.
Write a JavaScript code segment using a for loop that calculates and prints the product of the odd integers from 1 to 15, inclusive.
All programs can be written in terms of three control structures: _____________________, ______________________ and ___________________.

Rewrite the following code segment that uses a for loop as an equivalent code segment that uses a while loop.

    for (i = 1; i <= 10; i = i + 4)
    {
        if (i % 5 == 0)
	{
            alert(i + " is a multiple of 5.");
        }
        else
        {
            alert(i + " is not a multiple of 5.");
        }
    }

Rewrite the following code segment correcting all errors.

<script type="text/javascript">
  <!--
    /* This is my JavaScript comment
     * that spans more than 1 line.
     *
    document.write("<h1>Hello!<h1>"); 
  </script>
//-->

This question tests your knowledge of nested for loops. Please show line breaks in the proper places in the output. What is the output of the following code?

    var i, j;

    for (i = 0; i <= 3; i = i + 1)
    {
        for (j = 0; j <= 4; j = j + 1)
	{
	    if ( (i + 1 == j) )
	    {
	        document.write("+");
	    }
	    else
	    {
	        document.write("o");
	    }
	}
	document.write("<br />");
    }

In the nested for loop code above, how many times is the if statement executed?
Write a simple loop that prints out the following sequence of numbers: 18 23 28 33 38 43 48
Write a program that asks the user for two numbers and displays their product.
Write a program that prompts the user for 10 values and then displays their sum.

In the list below, circle the items that are NOT legal identfiers in JavaScript.

	3d               XyYzZx         ABC123

	__yes            star*it        m
	 
	me_to-2          main           money$

Determine the output of the following program segment:

	 var a = 2, b;

	 b = a;
	 document.write("b = " + b + "<br />");

	 b = b + 1;
	 document.write("b = " + b + "<br />");

	 b = a / b;
	 document.write("b = " + b + "<br />");

	 document.write("a = " + a + "<br />");

Given:
var a = 3, b = 7, c = 15;
Evaluate each expression below as TRUE or FALSE.
```
	_______   (1)    c / b  ==  2

	_______   (2)    c % b  <=  a % b

	_______   (3)    b + c / a  !=  c - a
```
Determine the output generated by the following JavaScript and HTML code segments, assuming the surrounding program code (whatever it is) works correctly.

    document.write("We sell ");
    document.write("C shells<br />");
    document.write("by the<br />sea shore<br />");

    <ul>
       <li>apples</li>
       <li>oranges</li>
       <li>pears</li>
    </ul>

    var i = 1, number = 0;

    do
    {
      number = number + i;
      i = i + 1;
    } while(i < 5);

    document.write("number is: " + number);

    var x = 1;

    if (x > 3) 
    {
        if (x > 4) 
        {
            document.write("A");
        } 
        else 
        {
            document.write("B");
        }
    } 
    else if (x < 2) 
    {
        if (x != 0) 
        {
            document.write("c");
        }
    }
    document.write("d");

    var j, k;

    for (j = 1; j <= 4; j = j + 1) 
    {
        for (k = 1; k <= j; k = k + 1) 
        {
            document.write("*");
        }
	document.write("<br />");
    }

    var g, h;

    for (g = 1; g <= 3; g = g + 1) 
    {
        for (h = 0; h < 3; h = h + 1) 
        {
            if (g != h) 
            {
                document.write("o");
            } 
            else 
            {
                document.write("x");
            }
        }
	document.write("<br />");
    }