Programming For Designers V3

Overcoming code fear

An introduction to programming for designers

Unintelligible - Yuk

^[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}$

But not all code is squiggles!

SUBTRACT Tax FROM GrossPay GIVING NetPay

So what is a script?

A script for a play defines a cast and gives them instruction to produce the desired result, a play.

A script for a computer could be said to be the same. It defines the resources and how they are used in a prescriptive manner to achieve a desired result. The words script and program can be used interchangeably.

Languages

BASIC, C++, Java, JavaScript, Lisp, SQL, PHP, Perl, Python, Ruby

Why is HTML not considered a programming language?

Why is ASP not on this list?

Learn one language and you have learned a lot about many others.

A standard HTTP request Request hello.HTML Browser Server hello.HTML <h1>Hello</h1> goodbye.HTML <h1>Hello</h1>

A standard HTTP request Response Browser Server hello..HTML <h1>Hello</h1> goodbye.HTML <h1>Bye</h1> <h1>Hello</h1>

A standard HTTP request Hello

A CGI Request Request hello. PHP Browser Server hello.PHP Echo “Hello”; goodbye.PHP Echo “Goodbye”;

A CGI Request Response hello.PHP Echo “Hello”; Browser Server goodbye.PHP Echo “Goodbye”; <h1>Hello</h1>

A CGI Request hello.PHP <?php echo “ <h1>Hello</h1> ”; ?>

A CGI Request Hello

Server Side vs Client Side Javascript Java Flash PHP Java ASP Client Server HTTP

Sequences

echo “<p>Hello</p>” ;

echo “<p>Goodbye</p>” ;

To Do:

Go Home

Make Tea

Wash Up

To Do:

Variables Name Price John 16.50

Variables Name Price Pete 16.50

Variables

$ price = 20;

$ name = “John”;

echo “Hello $ name, the price is £ $ price”;

$ name = “Pete”;

echo “Hello $ name, the price is £ $ price”;

$ tax = $ price * 0.15;

Input A PHP script Get Post Database Cookies Files Server Info To Do:

Output A PHP script HTML Database Cookies Files To Do:

Hello $name

$name = $_REQUEST[‘your_name’] ;

echo “<p>Hello $name </p>”;

helloform.HTML … … … <form action=“ helloreply.php ” method=“post”> <label>Your Name</label> <input type=“text” name=“your_name” /> <input type=“submit” /> </form> … … … helloreply.PHP <html> <head>…..</head> <body> <?php $name = $_REQUEST[‘your_name’]; echo “<p>Hello $name</p>” ; ?> </body> <html>

Expressions and operators

$counter + 1;

($quantity * $price) + $shipping

“ blue” . “bird”

1 < 2

$dog == “Spot”

$price != 44;

Selection – Hello maybe

$name = “Martin”;

if ($name != “John”)

{

echo “Hello!”;

}

else

{

echo “Goodbye!”;

}

To Do: Plan for today if it is hot then go outside otherwise stay in bed

A more useful Hello maybe

$name = $_REQUEST[‘your_name’];

if ($name != “Pete”)

{

echo “Hello!”;

}

else

{

echo “Goodbye!”;

}

hello.php?your_name=Mary

hello.php?your_name=Pete

Repetition (looping)

run a lap

until done 100 laps or completely knackered

$counter = 1;

while ( $counter <= 10 )

{

echo “$counter <br />”;

$counter = $counter + 1;

}

echo “Finished<br />”;

Functions

function fill_kettle ()

{

place kettle under tap;

turn on tap;

wait until kettle is full;

turn off tap;

}

fill_kettle ();

Hello function

hello();

function hello()

{

$name = $_REQUEST[‘name’];

echo “<p>Hello $name</p>”;

}

Hello parameter

<?php

welcome( “Jane” );

welcome($somebody);

function welcome( $name )

{

$message = “<p>Hello $name</p>”;

echo $message;

}

?>

Databases

Databases need code to retrieve data and translate into HTML

SQL is the most popular language for asking databases for data

PHP can talk to many databases using SQL but most often is paired with MySQL

SQL

SQL is used with other languages such as PHP

SELECT * FROM orders;

SELECT profile_pic FROM profiles WHERE profile_name = “Jimbo123”;

Let’s Design an App Twaddl.com What have you done today? Update Cooked a curry Went to work Jogged 2 miles

Twaddl Database ID Twaddl 1 Argued with girlfriend – again! 3 Went to work 4 Cooked a curry 2 Jogged 2 miles

Twaddl Main Program Flow Handle posted twaddl List twaddles

Handle Posted Twaddl Is submitted twaddle empty? Insert twaddle into database List twaddles No Yes Display an error message

List Twaddles Get list of twaddles from database End Program For each twaddle in list: Display twaddle

Complications! An example.

Ordinals: 1 st 2 nd 3 rd 4 th etc.

Mod: 53 % 10

function ordinal($number)

{

$last_digit = $number % 10;

if ($last_digit == 1) $ord = “st”;

elseif ($last_digit == 2) $ord = “nd”;

elseif ($last_digit == 3) $ord = “rd”;

else $ord = “th”;

echo $number . $ord;

}

Where from here?

PHP Lessons Online:

http://uk3. php .net/ tut . php

http://www. webmonkey .com/tutorial/PHP_Tutorial_for_Beginners

Tuition 

Programming For Designers V3

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Notes on slide 1

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