PHP

how to define function in php

<?php
function writeMsg() {
    echo "Hello world!";
}

writeMsg(); //call the function
?>

create function php

<?php
  #Syntax:
  function functionName() {
    code to be executed;
  }

  function Greetings() {
    echo "Hello, welcome!";
  }
  
  Greetings(); #Execute function 

  #Function arguements

  #Function arguements are just like prefixes/suffixes and can have multiple arguements

  function Polygon(str $prefix = penta, str $suffix = gon) {
    echo "$prefix$suffix"
  }

  Polygon("tetra", "gon");
  Polygon(); #Here, we use default value
  Polygon("hexa", "gon");
  Polygon("septa", "gon");
?>

define in php

//define() is used to create constants
define(name,value);
//here name has to be a string
//here value can be string, integer, float, boolean or NULL, 
//and can be an array to if you are using PHP 7.0+

//define() before php 7.3
define(name,value,case_insensitive);
//case_insensitive is optional and can be TRUE or FALSE by default its false

function in php

<?php
//am defining funciton here

function checkingResults($name, $marks){
    echo "hi ".$name;
    echo "<br/>";
    echo "Your total score: ".$marks;
}

checkingResults("denim", 125);
?>

function in php

                                                   // Function


function myFunctions($fname) {        // By using parameters we only need to pass arguments and we can only change parameter when we needed and print result. For example 
    echo $fname."<br>";                // if we make a function of sum and we want to change only values and want a result, thats why we use functions with parameters.
                                       // Here fname is a parameter. They also called formal parameters.
 }

 function myFunction($x, $y) {         // here x and y are formal parameters.
   int s;
   $s = $x+$y;
   return $x+$y;                     // 5+3 = 8   
   return s;                         // return 8 to the main function where it is invoked. And we can use the return value 
                                       // in main for any opration.
 }


                          // Compiler first read always main function OR where function is calling.

   myFunctions("Liam");                // Liam, Jenny and Anja are arguments. They also called actual
   myFunctions("Jenny");               // parameters. They passed their values to formal parameters.
   myFunctions("Anja");              
 
   echo "Enter two numbers";
   myFunction($a,$b);                  // values of a and b which user has been entered pass to formal parameter x and y in myFunction. After procssing in function the return value come in main function and cout(print) that return value.Here we passed a and b are calleed arguments. They also called actual parameters.
   //OR
   $c = myFunction($a,$b);             // We can store the value 8 which is return from myFunction in c variable and use it for further any operation.
   echo $c;                            // Now c = 8;
   //OR
   myFunction(5, 3);                   // return value of s from function arrive here and then print the answer.          
  


                               // Return Function

 We use return function when we have to use the value of that return function in main. If we not return value
 it can only use in that function. We cannot return more than one value from function.                                                



function sum($mth,$eng,$phy){
     $s = $mth+$eng+$phy;
     return $s;
 }

 function percentage ($totals){
     $per = $totals/300*100;
     return $per; 
 }

 $total = sum(80,85,90);

 echo $total. "<br>";

 $percentageNum = percentage($total);

 echo $percentageNum. "%";



                                        // Recursive Function


 function fact($n){                  // first n is 5. then 4,3,2,1
     if($n>1){
         return $n*fact($n-1);       // this is recursive statement which called fact function again and again
     }                               // with also reduce the value of n to 4,3,2,1;
     else{
         return $n;
         // return 1;             // At last 1 return to fact in return fact;
     }
 }

      $f = 5;
      echo fact($f);      // this f argument which is actual parameter is passed to function formal parameter
                     // of function fact. let f is 5.



 Step by step calculation of factorial(4)
 factorial(4) = 4 * factorial(3); 
 factorial(4) = 4 * 3 * factorial(2);
 factorial(4) = 4 * 3 * 2 * factorial(1);
 factorial(4) = 4 * 3 * 2 * 1;
 factorial(4) = 24;

 

define php

define("name", {value});

php function

 $myarray = array_filter($myarray, 'strlen');  //removes null values but leaves "0"
 $myarray = array_filter($myarray);            //removes all null values

define function in php

<?php

function addTwoNumbers($number1, $number2){
    echo "Result: ",$number1+$number2;
}

addTwoNumbers(100, 125);
?>

php function use

// Inherit $message
$example = function () use ($message) {
    var_dump($message);
};
$example();

PHP Functions

<?php
function writeMsg() {
  echo "Hello world!";
}

writeMsg(); // call the function
?>