Podcast
Questions and Answers
What does the URL 'http://www.facebook.com/home.php' specify?
What does the URL 'http://www.facebook.com/home.php' specify?
Server-side scripting allows users to view the server code from their browser.
Server-side scripting allows users to view the server code from their browser.
False
What does PHP stand for?
What does PHP stand for?
PHP Hypertext Preprocessor
The software that handles server-side programming and sends responses is called a ______.
The software that handles server-side programming and sends responses is called a ______.
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Match the following server-side programming languages with their characteristics:
Match the following server-side programming languages with their characteristics:
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Which of the following is NOT a benefit of server-side programming?
Which of the following is NOT a benefit of server-side programming?
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Apache is an example of web server software.
Apache is an example of web server software.
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What are commonly known purposes of server-side scripting?
What are commonly known purposes of server-side scripting?
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What is the correct result of the following operation: $5 + '7'?
What is the correct result of the following operation: $5 + '7'?
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In PHP, strings within single quotes interpret variables inside them.
In PHP, strings within single quotes interpret variables inside them.
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Which operator is used for string concatenation in PHP?
Which operator is used for string concatenation in PHP?
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In PHP, the function to calculate the length of a string is called ______.
In PHP, the function to calculate the length of a string is called ______.
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Match the PHP string functions with their Java equivalents:
Match the PHP string functions with their Java equivalents:
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What will the following code print? print 'You are $age years old.
';
What will the following code print? print 'You are $age years old. ';
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PHP uses zero-based indexing for string access.
PHP uses zero-based indexing for string access.
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What is the output of this code: print 'Ethiopian cuisine';?
What is the output of this code: print 'Ethiopian cuisine';?
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What function is used to get the current month in PHP?
What function is used to get the current month in PHP?
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In PHP, a for loop can be used to create a list of equations.
In PHP, a for loop can be used to create a list of equations.
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What is the output format for the squares of numbers 1-12 in PHP?
What is the output format for the squares of numbers 1-12 in PHP?
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In a multiplication table created with loops, the first row typically contains the values of ______.
In a multiplication table created with loops, the first row typically contains the values of ______.
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Match the following PHP concepts with their descriptions:
Match the following PHP concepts with their descriptions:
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What will be printed if the variable $age is not defined when trying to print 'Today is your $ageth birthday.'?
What will be printed if the variable $age is not defined when trying to print 'Today is your $ageth birthday.'?
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$name = NULL; if (isset($name)) will evaluate to TRUE.
$name = NULL; if (isset($name)) will evaluate to TRUE.
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In a for loop, how do you increment the variable $i by 1 in each iteration?
In a for loop, how do you increment the variable $i by 1 in each iteration?
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In PHP, the __________ statement is used for conditional branching.
In PHP, the __________ statement is used for conditional branching.
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Match the following data types with their example values:
Match the following data types with their example values:
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Which of the following values is considered FALSE in PHP?
Which of the following values is considered FALSE in PHP?
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The division of two integers always results in an integer in PHP.
The division of two integers always results in an integer in PHP.
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What will the following code print: echo (bool) 0;
What will the following code print: echo (bool) 0;
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The PHP function __________ returns the square root of a number.
The PHP function __________ returns the square root of a number.
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What is the output of the following code: for ($i = 0; $i < 3; $i++) { print $i; }?
What is the output of the following code: for ($i = 0; $i < 3; $i++) { print $i; }?
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Which of the following statements is NOT true about PHP?
Which of the following statements is NOT true about PHP?
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PHP variables are case insensitive.
PHP variables are case insensitive.
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What is the function used to print output to the console in PHP?
What is the function used to print output to the console in PHP?
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In PHP, all variable names begin with the symbol ______.
In PHP, all variable names begin with the symbol ______.
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Match the PHP data types with their descriptions:
Match the PHP data types with their descriptions:
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Which operator is used for division in PHP?
Which operator is used for division in PHP?
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PHP is a strictly typed programming language.
PHP is a strictly typed programming language.
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What type is the variable $drinking_age if defined as $drinking_age = $age + 5?
What type is the variable $drinking_age if defined as $drinking_age = $age + 5?
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Study Notes
URLs and Web Servers
- Typing a URL into your browser initiates a process involving DNS lookup for the server's IP address, establishing a connection to that address, and requesting the specified file.
- The web server software, such as Apache, retrieves the file from the server's local file system and sends its content back to your browser.
- Some URLs point to programs that the web server should run, sending their output back to you as the result.
Server-side Web Programming
- Server-side pages are programs written using various web programming languages/frameworks, including PHP, Java/JSP, Ruby on Rails, ASP.NET, Python, and Perl.
- Server-side scripting, also known as server-side programming, dynamically edits, changes, or adds content to web pages.
- It also allows responding to user queries, processing data submitted from HTML forms, accessing databases, and returning results to the browser.
Benefits of Server-side Programming
- Allows for web page customization for individual users.
- Provides security as server code cannot be viewed from a browser.
Web Server
- Contains software that enables running server-side programs.
- Sends back their output as responses to web requests.
What is PHP
- PHP stands for "PHP Hypertext Preprocessor" and is a server-side scripting language.
- Used to make web pages dynamic, providing different content based on context, interacting with other services, authenticating users, processing form information, and providing security.
- PHP code can be embedded within HTML.
Lifecycle of a PHP Web Request
- A user's request for a PHP file (e.g., hello.php) is sent to the web server.
- The server executes the PHP code within the file.
- The server sends back the generated HTML output to the user's browser.
Why PHP?
- PHP is free and open-source.
- It is compatible with various technologies, as it is used by millions of websites.
- PHP is a simple language, making it easy to learn and use.
PHP Basic Syntax
- PHP code within a .php file is executed between the opening and closing PHP tags (
<?php
and?>
). - All content outside the tags is treated as pure HTML.
- You can switch between HTML and PHP modes within a file.
Console Output: print
- The
print
function outputs text directly to the console. - It's similar to Java's
System.out.println
. - Escape sequences (“ and ) work the same way as in Java.
- Strings can be enclosed in double quotes (") for variable interpolation or single quotes (') for literal text.
Variables
- Variables are declared with a leading dollar sign ($) and assigned values using the
=
operator. - Variable names are case-sensitive.
- PHP is loosely typed; you don't need to explicitly declare the data type.
- Basic types include
int
,float
,boolean
,string
,array
,object
, andNULL
. - PHP automatically converts between types in many cases.
Arithmetic Operators
- Includes operators like
+
,-
,*
,/
,%
,++
,--
, and assignment operators. - Many operators automatically convert types, e.g.,
5 + "7"
results in 12.
Comments
- Use hash symbol
(#)
or double slash(//)
for single-line comments. - PHP code often uses
#
comments instead of//
.
String Type
- String variables are declared with the
=
operator and hold textual data. - Zero-based indexing using square brackets is used to access characters within a string.
- String concatenation uses the dot (
.
) operator, not the plus (+) operator. - Strings can be in either double quotes (") or single quotes (').
String Functions
- PHP provides functions to work with strings, mirroring Java equivalents.
- These functions include:
-
strlen
: Equivalent to Java'slength
. -
strpos
: Equivalent to Java'sindexOf
. -
substr
: Equivalent to Java'ssubstring
. -
strtolower
,strtoupper
: Equivalent to Java'stoLowerCase
,toUpperCase
. -
trim
: Equivalent to Java'strim
. -
explode
,implode
: Equivalent to Java'ssplit
,join
. -
strcmp
: Equivalent to Java'scompareTo
.
-
Interpreted Strings
- Strings enclosed in double quotes ("") are interpreted, meaning variables inside them will be replaced with their values.
- Strings enclosed in single quotes (') are not interpreted; variable names remain as literal text.
- If ambiguity is a concern, you can use curly braces
{}
to enclose a variable within a string.
NULL, isset Function
- A variable is considered
NULL
when:- It has not been assigned a value (undefined variables).
- It has been assigned the
NULL
constant. - It has been deleted using the
unset
function.
- The
isset
function tests whether a variable has been set and is notNULL
.
For Loop (Same as Java)
- The
for
loop structure is identical to Java. - It uses initialization, condition, and update statements for iteration.
Bool (Boolean) Type
- Boolean values are represented by
TRUE
andFALSE
. -
FALSE
values include:- 0 and 0.0
- "", "0", and
NULL
(including unset variables) - Arrays with zero elements.
-
FALSE
prints as an empty string, whileTRUE
prints as 1.
If/Else Statement
- The
if/else
statement structure is the same as in Java.
While Loop (Same as Java)
- The
while
anddo-while
loop structures are identical to Java.
Math Operations
- PHP offers various math functions, including:
-
sqrt
: Square root. -
pow
: Raise to a power. -
abs
: Absolute value. -
ceil
,floor
,round
: Rounding functions (round
outputs a float). -
log
,log10
: Logarithm calculations. -
max
,min
: Finding maximum and minimum values. -
rand
: Generate random numbers. -
sin
,cos
,tan
: Trigonometric calculations.
-
- It also provides math constants:
-
M_PI
: Value of pi. -
M_E
: Value of Euler's number. -
M_LN2
: Natural logarithm of 2.
-
Int and Float Types
-
int
represents integers, whilefloat
represents real numbers. - Division between two integers can result in a float value.
- Type casting can be used to explicitly convert between these types.
PHP Exercise 1
- Echo the string "Twinkle, Twinkle little star." to the browser.
- Create two variables, one for "Twinkle" and the other for "star."
- Write a script that gets the current month and prints a message indicating if it's August or not.
PHP Exercise 6
- Use a for loop to generate a list of squares from 1 to 12, showing each formula ("1 * 1 = 1") on a separate line.
PHP Exercise 7
- Create a multiplication table for numbers 1-7 using nested for loops.
- The table should display the product of each row and column combination.
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Description
This quiz covers the essentials of web server programming, including how URLs interact with web servers and the use of server-side programming languages such as PHP and Python. Learn about the functions and benefits of server-side scripting in creating dynamic web pages and processing user data.