CODE EXAMPLE FOR PHP

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;