# Factorial program in PHP

In this program, you will find factorial of number by using loop.
i) for loop
ii) while loop
iii) do while loop
2) using recursive function
3) using HTML form

factorial of a number is the multiplication of all its below number.
for example: 5! = 5*4*3*2*1 = 120

## Factorial program in PHP using for loop

In this program factorial of 5 using the for loop program is shown:

``````<?php
\$n=5;
\$fact=1;
for(\$i=1;\$i<=\$n;\$i++){
\$fact=\$fact*\$i;
}
echo "factorial of 5 is: \$fact";
?>``````

## output

`factorial of 5 is: 120`

## Factorial program in PHP using while loop

In this program factorial of 6 using the while loop program is shown:

``````<?php
\$n=6;
\$fact=1;
\$i=1;
while(\$i<=\$n){
\$fact=\$fact*\$i;
\$i++;
}
echo "factorial of 6 is: \$fact";
?>``````

## output

`factorial of 6 is: 720`

## Factorial program in PHP using do while loop

In this program factorial of 4 using do while loop program is shown:

``````<?php
\$n=4;
\$fact=1;
\$i=1;
do{
\$fact=\$fact*\$i;
\$i++;
}while(\$i<=\$n);
echo "factorial of 4 is: \$fact";
?>``````

## output

`factorial of 4 is: 24`

## Factorial program in PHP using recursion

In this program factorial of 5 using the recursive method program is shown:

``````<?php
function factorial(\$n)
{
if(\$n>1)
{
return \$n*factorial(\$n-1);
}
else{
return 1;
}
}
echo "factorial of 5 is:".factorial(5);
?>``````

## output

`factorial of 5 is:120`

## Factorial program using HTML form in PHP

``````<!DOCTYPE html>
<html lang="en">
<title>factorial program</title>
<body>
<form>
Enter the number <input type="number" name="factorial">
<input type="submit" value="submit" name="click"></br>
</form>
</body>
</html>
<?php
if(isset(\$_GET["click"]))
{
\$n=\$_GET['factorial'];
\$fact=1;
\$i=1;
while(\$i<=\$n){
\$fact=\$fact*\$i;
\$i++;
}
echo "factorial of \$n is: \$fact";
}
?>``````