Web Application Development

1
Web Application Development

• Seminar 2 Part I
• CMWA 6103
• Jaspal Kaur

2
Arrays

• An array is a variable that stores a set or
  sequence of values.
• One array can have many elements, each element
  can hold a single value such as text or numbers
  or another array.

3
Initializing Arrays

• Example of array
• products array(Tires,Oil,Spark Plugs)
• numbers range(1,10)
• odds range(1,10,2)
• letters range(a, z)

4
Accessing Array Contents

• To access the contents of a variable, you use its
  name. The key or index indicates which of the
  values in the array you access.
• products0, products1, products2
• Add a new element products3 Fuses
• Displaying the contents echo products0
  products1 products2 products3
• Using loops to display array contents
• for (i 0 ilt3 i)
• echo productsi

5
Arrays with different Indices

• Initializing an array
• prices array (Tiresgt100, Oilgt10, Spark
  Plugsgt 4)
• To access the array elements
• foreach(prices as key gt values)
• echo key.gt.value.ltbr /gt

6
Multidimensional Arrays

• Two-D array matrix, grid with width and heigth
  or row and cols.
• Example
• products array (array (TIR, Tires,100),
  array (OIL, Oil, 10),
• array (SPK,
  Spark Plugs,4) )

7
Accessing Multidimensional Arrays

• for (row 0 row lt 3 row)
• for (column 0 column lt 3 column)
• echo .productsrowcolumn
• echo ltbr /gt

8
Sorting Arrays

• Using sort()- sort into alphabetical order
• products array (Tires, Oil, Spark
  Plugs)
• sort (products)
• Now the order will be Oil, Spark Plugs, Tires
• Sort() is case sensitive, Capital letters before
  lowercase letters,
• Sorting in reverse rsort().

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Reordering arrays

• shuffle()-randomly reorders the elements in the
  array.
• array_reverse() creates a new array in the
  reverse order of the original.
• Navigating within an array each(), current(),
  reset(), end(), next(), pos(), and prev().
• Counting elements in an array count(),
  sizeof(), array_count_values().

10
String Manipulations

• Formatting Strings
• Presentation
• Joining and Spliting Strings
• Comparing Strings

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Formatting Strings

• Trimming Strings chop(), ltrim(), and trim()
• Example
• name trim (name)
• email trim (email)
• feedback trim (feedback)

12
Formatting Strings for Printing

• print() and echo() prints the string as it is.
• printf() and sprintf() prints and returns a
  formatted string.
• Example
• echo Total amount of order is total.
• printf(Total amount of order is s., total)

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Changing the Case of a String

• strtoupper() turns string to uppercase
• strtolower() turns string to lowercase
• ucfirst() Capitalizes first character of string
  if its alphabetic
• ucwords() Capitalizes first character of each
  word in the string that begins with an alphabetic
  character

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Joining and Spliting Strings

• explode() splits a string based on a specified
  separator string as an array
• implode(), join() reverse of explode()
• strtok() gets pieces (tokens) from string one
  at a time
• substr() access a substring between given start
  and end points of the string

15
Comparing Strings

• strcmp() expects two strings and compares them,
  if they are equal, returns 0, otherwise if str1
  is greater than str2, returns number greater than
  0.
• strcasecmp() is not case sensitive
• strnatcmp() compares strings according to
  natural ordering (2 before 12).

16
Object oriented PHP

• Classes and Objects
• object is any item or concept
• o-o software designed and built as a set of
  self-contained objects with attributes and
  operations that interact
• Attributes properties or variables
• Operations methods, actions or functions

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Object-oriented Concepts

• Encapsulation
• Polymorphism
• Inheritance

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Creating classes, atributes, operations in PHP

• Creating a class in PHP
• class classname
• Attributes and operations
• class classname
• var attribute1
• var attribute2
• function operation1()

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Constructors Destructors

• Constructors called when an object is created,
  used for initialisation
• _construct()
• Can be called manually or explicitly
• Can be overloaded
• Destructors executed automatically just before
  class is destroyed, or when all references to a
  class have fallen out of scope.
• _destruct()
• Cannot take parameters (overloaded)

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Instantiating Classes

• to create an object, new keyword is used
• Example
• class classname
• function _construct(param)
• echo Constructor called with
  parameter param ltbr /gt
• a new classname (First)
• b new classname (Second)
• c new classname ()

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Using Attributes Operations

• special pointer this
• accessing attributes a-gtattribute
• _get() and _set() to return and set attributes
• a-gtattribute 5 uses _set()
• a-gtattribute uses _get()
• a-gtoperation1()
• y a-gtoperation2(12, test)

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Public and Private

• Access modifiers control visibility of attributes
  and methods
• public (default) accessed in and out of class
• private only accessed from within
• protected accessed from within and subclasses

23
Implementing Inheritance

• class B extends A
• var attribute2
• function operation2()
• function operation1()
• different codes .
• class A
• var attribute1
• final function operation1()

b new B() b-gtoperation1() b-gtattribute1
10 b-gtoperation2() b-gtattribute2 10 a
new A() a-gtoperation1() a-gtattribute1
10 a-gtoperation2() a-gtattribute2 10
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Overriding

• subclass may redeclare the same attributes and
  operations
• different default value or different
  functionality of operations from the superclass
• inheritance and overriding can be prevented using
  final keyword

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Interfaces

• uses multiple inheritance concept
• specifies a set of functions that must be
  implemented by the class
• only prototypes operations are listed in the
  interface
• classes can only extend one superclass but can
  implement many interfaces

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End of Part I

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