PHP Functions

A function is a block of code that can be defined and then called to perform a specific task. It helps in organizing code into modular and reusable, making it easier to manage and maintain.

Advantages of Using Functions:

• Readability
• Organizing
• Reusability
• Maintenance
• Easy to Understand

1. Creating a Function.

It is very simple to create a php function. The syntax for declaring and calling functions in PHP is:

Syntax:

<?php
	function name()
	{
 		// code to be executed
	}
?>

Example

<?php
	function output()
	{
 		echo "Hello Learners";
	}
?>

Output:

2. Calling a function:

For calling a function just call it by using its name followed by parentheses.

Syntax:

<?php
   function name()
   {  
       // code to be executed 
   }
   name(); //calling a function
?>

Example:

<?php
   function output(){  
       echo "Hello Learners";  
   }
   output(); // calling function
?>

Output:

3. Calling a function by arguments:

Php functions has an option to pass information through arguments. An argument is like a variable.

When we define a function, we can specify parameters, which act as placeholders for values that the function will receive when it's called. These parameters are declared in the function's parentheses.

Syntax:

<?php
   // Function definition with parameters
   function name($parameter1, $parameter2, /* ... other parameters */)
   {
       // Function body, where you can use $parameter1, $parameter2, etc.
       // Perform operations or return a value if needed
   }
   // Example usage
   $value1 = /* some value */;
   $value2 = /* some value */;
   // Call the function with arguments
   name($value1, $value2 /*, ... other arguments */);
?>

Example:

<?php
   // Function definition with parameters
   function multiply($a, $b) {
       $product = $a * $b;
       echo "The product of $a and $b is: $product";
   }
   // Example usage
   $value1 = 5;
   $value2 = 10;
   // Call the function with arguments
   multiply($value1, $value2);
?>

Output:

Note:  You can have functions with zero parameters (no parameters), one parameter, two parameters, and so on, separated with comma.

4. Php default arguments

We can assign default values to function parameters. If a value is not provided when the function is called, the default value will be used. This is useful when you want to make certain parameters optional.

Example:

<?php
   // Function with default argument values
   function greet($name = "LearnCoding", $greeting = "Hello") {
       echo "$greeting, $name!";
   }
   
   // Example usage
   greet(); // Uses default values: "LearnCoding" and "Hello"
   echo "<br>";
   greet("John"); // Uses default value for $greeting: "Hello"
   echo "<br>";
   greet("Geek", "Good morning"); // Uses provided values:"Geek" and "Good morning"        
?>

Output:

5. PHP Functions - Returning values

A function can return a value using the ‘return’ statement in the function. The value returned by the function can be used in the calling code.

Example:

<?php
   // Function that returns the sum of two numbers
   function addNumbers($a, $b) {
       $sum = $a + $b;
       return $sum;
   }
   
   // Example usage
   $result = addNumbers(5, 10);
   
   // Print the result
   echo "The sum is: $result";        
?>

Did you Know?

Php has over 1,000 built-in functins that can be called directly.