PHP Programs for Practice
1. An example of Variables.
<?php
$str=”Hello World”;
$X=10;
$y=15.75;
echo $str,”<br/>”;
echo $X, “<br/>”;
echo $y;
?>
2. An example of assigning values to Variables.
<?php
$num=22;
$square=$num * $num;
$script='PHP';
echo "<br/>Script $script";
echo "<br/>Number $num";
echo "<br/>Square $square";
?>
3. An example of Reference Assignment.
<?php
$script1="ASP";
$script2=&$script1;
echo "$script1<br/>";
echo "$script2<br/>";
$script2="PHP";
echo "$script1<br/>";
echo "$script2<br/>";
?>
4. An example of Variable of Variable.
<?php
$varname='number';
$$varname=5;
echo $varname;
echo "<br/>";
echo $number;
echo "<br/>";
echo $$varname;
?>
5. An example of Global Variable.
<?php
$x = 10;
function printx()
{
GLOBAL $x; //Global Variable
$x = 0;
print "X inside function is $x. <br>";
}
printx();
print "X outside of function is $x. <br>";
?>
6. An example of Static Variable.
<?php
function countn()
{
STATIC $c=0;
$c++;
echo "<br/>Call ".$c;
}
countn();
countn();
countn();
?>
7. An example to Remove Variable.
<?php
$script='PHP';
echo $script;
unset($script);
echo $script;
?>
8. An example to define a constant using define().
<?php
define("script","PHP Script");
echo script; //Constant is accessed without $ symbol
?>
9. An example to define a constant using const.
<?php
const shape="Circle";
echo shape;
?>
|
Const
|
Define()
|
|
Const defines
the constants at compile time.
|
Define() defines
the constants at run time.
|
|
Const cannot
define constants conditionally.
|
Define() can be
used define constants conditionally.
|
|
Constants
defined by const are case-sensitive.
|
Constants
defined by define() can be case-insensitive.
|
|
Const takes
static scalar values (number, string or other constant like true, false,
null)
|
Whereas define() accepts
any expression as name.
|
|
const defines
a constant in the current namespace.
|
define()
has to be passed the full namespace.
|
10. An example to prove constants are global.
<?php
define("SCRIPT", "PHP Script");
function myScript()
{
echo SCRIPT;
}
myScript();
echo "<br/>";
echo SCRIPT;
?>
11. Predefined Constants
A. __LINE__ Constant: -This constant returns the current line number of the file. It returns the line number in the source file where it is used.
<?php
echo "Good Morning <br/>";
echo "<br/>Line Number ".__LINE__;
echo "<br/>Line Number ".__LINE__;
echo "<br/>Line Number ".__LINE__;
?>
B. __FILE__ Constant:-This constant returns the full path and the name of the source file that’s being executed.
<?php
echo "<b>Displaying the name of the File <br/>";
echo "<br/>File Path and Name ".__FILE__;
?>
C. __DIR__ Constant: -This constant returns the name of the directory in which source file is stored. It returns the path without file name.
<?php
echo "<b>Displaying the Directory of the File <br/>";
echo "<br/>File Path and Directory".__DIR__;
?>
D. __FUNCTION__ Constant: -This constant returns the name of function in which it is used.
<?php
echo "<b>Displaying the Function Name</b><br/>";
function fun()
{
echo "<br/>The Name of function is : - ".__FUNCTION__;
}
fun();
?>
5. __CLASS__ Constant: -This constant returns the name of the class in which it is used.
<?php
class myClass
{
public function showName()
{
echo __CLASS__;
}
}
$nm=new myClass();
echo "The name of the class : - ";
$nm->showName();
?>
E. __METHOD__ Constant: -This constant returns the name of class method in which it is used.
<?php
class myClass
{
public function showName()
{
echo __METHOD__;
}
}
$nm=new myClass();
echo "The name of the class method : - ";
$nm->showName();
?>
7. __NAMESPACE__ Constant: -This constant returns the name of the namespace used in the source code.
<?php
namespace MyNameSpace;
echo "The namespace used in this program - ", __NAMESPACE__;
?>
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