# PHP Program - Power of a Number

If **power (or exponential)** of number indicates how many the number is multiplied by itself to get the final number. For example:

*x* raised to the power *2* = x² = x*x

*x* raised to the power *3* = x³ = x*x*x

### Example: Using conditional statement

In the below example, a function called *Power()* is created to calculate power of a number. It uses *while* loop to achieve this. This method can be used to calculate the power of a number where power should be a non-negative integer.

<?php function Power($x, $n) { $finalnum = 1; $n1 = $n; while($n1 > 0){ $finalnum = $finalnum * $x; $n1--; } echo "$x raised to the power $n = $finalnum \n"; } Power(3, 5); Power(5, 0); Power(6, 2); ?>

The above code will give the following output:

3 raised to the power 5 = 243 5 raised to the power 0 = 1 6 raised to the power 2 = 36

### Example: Using pow() function of PHP

The pow() function of PHP <cmath> header file can also be used to calculate power of a number. It can be used to calculate *x ^{n}* for any value of n (n can be negative or fraction).

<?php $x = 3; $y = 5; $z = 6; $a = 5; $b = 0; $c = 2; echo "$x raised to the power $a = ".pow($x, $a)."\n"; echo "$y raised to the power $b = ".pow($y, $b)."\n"; echo "$z raised to the power $c = ".pow($z, $c)."\n"; ?>

The above code will give the following output:

3 raised to the power 5 = 243 5 raised to the power 0 = 1 6 raised to the power 2 = 36