Control Structures In Php 2
kfeighery
2,690 views
13 slides
Feb 01, 2009
Slide 1 of 13
1
2
3
4
5
6
7
8
9
10
11
12
13
About This Presentation
No description available for this slideshow.
Slide Content
Control Structures in PHP
Control Structures – if
statements
if ($a > $b)
echo "a is bigger than b";
if ($a > $b)
{print "a is bigger than b";
$b = $a;}
if ($a > $b)
{print "a is bigger than b"; }
else {print "a is NOT bigger than b"; }
if ($a > $b)
{print "a is bigger than b"; }
elseif ($a == $b)
{print "a is equal to b"; }
else {print "a is smaller than b“; }
statements
if ($a > $b)
echo "a is bigger than b";
if ($a > $b)
{print "a is bigger than b";
$b = $a;}
if ($a > $b)
{print "a is bigger than b"; }
else {print "a is NOT bigger than b"; }
if ($a > $b)
{print "a is bigger than b"; }
elseif ($a == $b)
{print "a is equal to b"; }
else {print "a is smaller than b“; }
Example usage
Example
<html>
<head><title>Your browser</title></head>
<body>
<h1>Your Browser</h1>
<p>
<?php
if( strstr($HTTP_USER_AGENT,"MSIE") )
{ echo "You are using Internet Explorer"; }
?>
to view this page.
</p>
</body>
</html>
strstr is a function which checks if its 2
nd
argument is a substring of its 1
st
Example
<html>
<head><title>Your browser</title></head>
<body>
<h1>Your Browser</h1>
<p>
<?php
if( strstr($HTTP_USER_AGENT,"MSIE") )
{ echo "You are using Internet Explorer"; }
?>
to view this page.
</p>
</body>
</html>
strstr is a function which checks if its 2
nd
argument is a substring of its 1
st
Control constructs -- looping
In PHP we have the following looping
statements:
while - loops through a block of code if and as
long as a specified condition is true
do...while - loops through a block of code once,
and then repeats the loop as long as a special
condition is true
for - loops through a block of code a specified
number of times
foreach - loops through a block of code for each
element in an array
In PHP we have the following looping
statements:
while - loops through a block of code if and as
long as a specified condition is true
do...while - loops through a block of code once,
and then repeats the loop as long as a special
condition is true
for - loops through a block of code a specified
number of times
foreach - loops through a block of code for each
element in an array
Control constructs -- while
These are just like their counterparts in C
$i = 1;
while ( $i <= 10 )
{ echo $i++; }
$i = 0;
do { print $i;} while ($i>0);
These are just like their counterparts in C
$i = 1;
while ( $i <= 10 )
{ echo $i++; }
$i = 0;
do { print $i;} while ($i>0);
Control constructs -- for
These are just like their counterparts in C
for ($i = 1; $i <= 10; $i++)
{ print $i;}
These are just like their counterparts in C
for ($i = 1; $i <= 10; $i++)
{ print $i;}
Control constructs -- foreach
These are similar their counterparts in Perl
foreach(array_expression as $value)
statement
foreach(array_expression as $key => $value)
statement
<?php
$arr=array("one", "two", "three");
foreach ($arr as $value)
{echo “Number: " . $value . "<br />";}
?>
These are similar their counterparts in Perl
foreach(array_expression as $value)
statement
foreach(array_expression as $key => $value)
statement
<?php
$arr=array("one", "two", "three");
foreach ($arr as $value)
{echo “Number: " . $value . "<br />";}
?>
Jumping in and out of PHP
mode
We can jump in and out of PHP mode even in the
middle of a PHP block:
<?php
if(strstr($HTTP_USER_AGENT,"MSIE"))
{ ?> <p>You are using Internet Explorer</p> <?php }
else { ?> <p>You are not using Internet Explorer</p> <?php }
?>
Instead of using an echo statement to print
something, we jumped out of PHP mode.
Note that the logical flow of the PHP remains intact
Only one of the HTML blocks will be sent to the user.
mode
We can jump in and out of PHP mode even in the
middle of a PHP block:
<?php
if(strstr($HTTP_USER_AGENT,"MSIE"))
{ ?> <p>You are using Internet Explorer</p> <?php }
else { ?> <p>You are not using Internet Explorer</p> <?php }
?>
Instead of using an echo statement to print
something, we jumped out of PHP mode.
Note that the logical flow of the PHP remains intact
Only one of the HTML blocks will be sent to the user.
A FORM and its handler in one
<html>
<head>
<title>Application Handler</title>
</head>
<body>
<?php
if (! $_POST["surname"] or !$_POST["address"]){
?>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
<p>Your surname: <input type="text" name="surname"></p>
<p>Your address: <input type="text" name="address"></p>
<input button type="submit" value= "Please send me the brochure.">
</form>
<?php
}
else{
$sn = $_REQUEST['surname'];
echo "<p>Thank you, $sn.</p>";
$addr = $_REQUEST['address'];
echo "<p> We will write to you at $addr .</p>";
}
?>
</body>
</html>
<html>
<head>
<title>Application Handler</title>
</head>
<body>
<?php
if (! $_POST["surname"] or !$_POST["address"]){
?>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
<p>Your surname: <input type="text" name="surname"></p>
<p>Your address: <input type="text" name="address"></p>
<input button type="submit" value= "Please send me the brochure.">
</form>
<?php
}
else{
$sn = $_REQUEST['surname'];
echo "<p>Thank you, $sn.</p>";
$addr = $_REQUEST['address'];
echo "<p> We will write to you at $addr .</p>";
}
?>
</body>
</html>
Finding out about your PHP
environment
One of the many pre-defined PHP functions is
phpinfo()
<html>
<body>
<h1>Your PHP Environment</h1>
<?php phpinfo(); ?>
</body>
</html>
In what follows, notice that mySQL support is
enabled
environment
One of the many pre-defined PHP functions is
phpinfo()
<html>
<body>
<h1>Your PHP Environment</h1>
<?php phpinfo(); ?>
</body>
</html>
In what follows, notice that mySQL support is
enabled
Adding Comments to a PHP
Script
Comments are nonprinting lines
placed in code such as:
The name of the script
Your name and the date you created the
program
Notes to yourself
Instructions to future programmers who
might need to modify your work
Script
Comments are nonprinting lines
placed in code such as:
The name of the script
Your name and the date you created the
program
Notes to yourself
Instructions to future programmers who
might need to modify your work
Adding Comments to a PHP
Script (continued)
Line comments hide a single line of
code
Add // or # before the text
Choose and stick with version
Block comments hide multiple lines of
code
Add /* to the first line of code
And */ after the last character in the code
Script (continued)
Line comments hide a single line of
code
Add // or # before the text
Choose and stick with version
Block comments hide multiple lines of
code
Add /* to the first line of code
And */ after the last character in the code
Example Comments
<?php
/*
This line is part of the block comment.
This line is also part of the block comment.
*/
echo (“<h1>Comments Example</h1>”); // Line comments
can follow
code statements
// This line comment takes up an entire line.
# This is another way of creating a line comment.
/* This is another way of creating
a block comment. */
?>
<?php
/*
This line is part of the block comment.
This line is also part of the block comment.
*/
echo (“<h1>Comments Example</h1>”); // Line comments
can follow
code statements
// This line comment takes up an entire line.
# This is another way of creating a line comment.
/* This is another way of creating
a block comment. */
?>
Categories
GeneralDownload
Download Slideshow Get the original presentation fileQuick Actions
Statistics
- Views 2,690
- Slides 13
- Age 6147 days
Related Slideshows
22
Pray For The Peace Of Jerusalem and You Will Prosper
RodolfoMoralesMarcuc
30 views
26
Don_t_Waste_Your_Life_God.....powerpoint
chalobrido8
32 views
31
VILLASUR_FACTORS_TO_CONSIDER_IN_PLATING_SALAD_10-13.pdf
JaiJai148317
30 views
14
Fertility awareness methods for women in the society
Isaiah47
29 views
35
Chapter 5 Arithmetic Functions Computer Organisation and Architecture
RitikSharma297999
26 views
5
syakira bhasa inggris (1) (1).pptx.......
ourcommunity56
28 views