PHP Variables
PHP Data Types
PHP Echo & Print
PHP Strings
PHP Numbers
PHP Constants
PHP Operators
PHP if...else...elseif Statements
Switch Statement
PHP Loops
PHP Arrays
Superglobals
PHP Coding Standards
PHP Form Handling
PHP Form Validation
PHP URLs Validation
PHP Form Required Validation
Complete Form Example
PHP File Functions Open/Read
PHP File Create/Write
PHP File Upload
PHP Cookies Handling
PHP Session Handling
PHP filter_var() Function
PHP Validation Filters
PHP Sanitization Filters
Using Filters
Filters Advanced
JSON
PHP Date and Time
MySQL Database
MySQL Connect
MySQL Commands-Creating a Table
MySQL Commands-Inserting The data
MySQL Commands-Prepared Statement
MySQL Commands-Selecting The Data
MySQL Commands-Where and Order By
MySQL Commands-Deleting And Updating The Data
PHP-OOP Introduction
PHP-Classes/Objects
PHP-Constructor/Destructor
PHP-Access Modifiers
PHP-Inheritance
PHP-Inheritance and Protected Access Modifier
PHP-Overriding Inherited Methods
PHP-Final keyword
PHP-Abstract Classes
PHP-Constants
PHP-Traits
PHP-Static Methods and Properties
Introduction to Functions
Defining A function
Returning Values From A Function
Dynamic Function Calls
Variable Scope
Understanding Arguments Or Parameters
Testing For A Function Existence
Returning Multiple Values From A Function
Making practical Use By Building Code Libraries For Code Re-usability
Using Include() And Require()
A variable used within the function’s curly parenthesis is known as parameters or arguments. They are basically the placeholders that hold values at runtime. You can use as many arguments or parameters in function as you require. Use a comma to separate the parameters. These parameters accept inputs at runtime when the function is called.
>Default Parameters
You can also set default values to the parameters in the function. When the user doesn’t provide any input, then these default values are used to the set the argument value in PHP.
For example:
function age($name, $x=18)
{
echo “$name is $x years old \n”;
}
age(“Kiara”,22); //Calling function with both parameters
age(“Allen”); //Calling function with default parameter
?>
Output of the above code will be
Kiara is 22 years old
Allen is 18 years old
>Passing Values to Function
We can pass parameters to functions in two ways using PHP.
Pass by value – In this method, the value of parameter gets changed inside the function, and the original value remains unchanged, i.e. a duplicate value is passed to the function.
Pass by Reference – In this method, the original value is passed to the function, and the original value gets changed. We pass the address of the value using this method where the value is stored using &.
For example
//Passing parameter by value
function valpass($x)
{
$x +=10;
return $x;
}
//Passing parameter by reference
function refpass(&$x)
{
$x +=10;
return $x;
}
$y =5;
valpass($n);
echo” Value remains unchanged and is $n
”;
refpass($n);
echo” Value changed by function and is $n”;
?>
The output of the above code will be:
Value remains unchanged and is 5
Value changed by function and is 15
So, the variable value is not changed when we pass by value, but the original value gets changed when we pass by reference.
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