Wednesday, September 6, 2017

PHP also supports recursive function call like C/C++,java etc.In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.

Example -1 :
Lets see the simple programming logic to print number using recursive function.
```<?php
function display(\$number) {
if(\$number<=15){
echo "\$number <br/>";
display(\$number+1); // calling a function again
}
}

display(10);
?>```
Output:
---------------------------------------
10
11
12
13
14
15

Example -2 :
Lets see the simple example to find the factorial of number using recursive function.
```<?php
function factorial(\$n)
{
if (\$n < 0)
return -1; /*Wrong value*/
if (\$n == 0)
return 1; /*Terminating condition*/
return (\$n * factorial (\$n -1));
}

echo factorial(7);
?>```
Output :
-----------------------------
5040

Example - 3 :
Lets see the simple example of Fibonacci series using the function recursion.
```<?php
/* Print fiboancci series upto 10 elements. */
\$num = 10;
echo "<h3>Fibonacci series using recursive function:</h3>";
echo "\n";
/* Recursive function for fibonacci series. */
function series(\$num){
if(\$num == 0){
return 0;
}else if( \$num == 1){
return 1;
}  else {
return (series(\$num-1) + series(\$num-2));
}
}
/* Call Function. */
for (\$i = 0; \$i < \$num; \$i++){
echo series(\$i);
echo "\n";
}
?>```
Output :
-------------------------------------

Fibonacci series using recursive function:

0 1 1 2 3 5 8 13 21 34