# Basic PHP Programs

## Add two numbers Program in PHP

```
<?php
$a=10;
$b=20;
$c=$a+$b;
echo "Sum: ",$c;
?>
```

## Swap Two number Program in PHP

Swap two number with each other means interchange their value. Suppose you have two number a and b a contain 10 and b contain value 20 after swap their value, a have 20 and b have 10.

```
<?php
$a=10;
$b=20;
echo "Value of a: $a</br>";
echo "Value of b: $b</br>";
$temp=$a;
$a=$b;
$b=$temp;
echo "Value of a: $a</br>";
echo "Value of b: $b</br>";
?>
```

## Swap two number without using third variable program in PHP

```
<?php
$a=10;
$b=20;
echo "Value of a: $a</br>";
echo "Value of b: $b</br>";
$a=$a+$b;
$b=$a-$b;
$a=$a-$b;
echo "Value of a: $a</br>";
echo "Value of b: $b</br>";
?>
```

## Even Odd number Program in PHP

Ever number are those which is divisible by 2 and odd numbers are not divisible by 2. For Example 10 is divisible by 2 so it is even number.

```
<?php
$num=10;
if($num%2==0)
{
echo "Even number";
}
else
{
echo "Odd number";
}
?>
```

## Factorial of a number in PHP

In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. But here we write program; how to print factorial of any number in php.

Example of Factorial :

5!= 5

4321 = 120

```
<?php
$num = 4;
$factorial = 1;
for ($x=$num; $x>=1; $x--)
{
$factorial = $factorial * $x;
}
echo "Factorial of $num is $factorial";
?>
```

## Armstrong number Program in PHP

A Armstrong number is a number that is the sum of its own digits each raised to the power of the number of digits is equal to the number itself..

```
<?php
$num=153;
$sum=0;
$temp=$num;
while($temp!=0)
{
$rem=$temp%10;
$sum=$sum+$rem*$rem*$rem;
$temp=$temp/10;
}
if($num==$sum)
{
echo "Armstrong number";
}
else
{
echo "not an armstrong number";
}
?>
```

## Palindrome number Program in PHP

Palindrome number means number remain same after reverse any number. For example we reverse 121 result will be 121 so it is palindrome number.

- Steps to check number is palindrome or not
- Take a number.
- Reverse the input number.
- Compare both the numbers.

```
<?php
$num = 121;
$p=$num;
$revnum = 0;
while ($num != 0)
{
$revnum = $revnum * 10 + $num % 10;
//below cast is essential to round remainder towards zero
$num = (int)($num / 10);
}
if($revnum==$p)
{
echo $p," is Palindrome number";
}
else
{
echo $p." is not Palindrome number";
}
?>
```

## Prime number Program in PHP

Here we can write php program to find number is prime or not using for loop. Here also same concept apply like C programming

```
<?php
$num =23;
for( $j = 2; $j <= $num; $j++ )
{
for( $k = 2; $k < $j; $k++ )
{
if( $j % $k == 0 )
{
break;
}
}
if( $k == $j )
echo "Prime Number : " . $j . '<br>';
}
?>
```

## Fibonacci Series Program in PHP

The simple concept to find fibonacci series is; add two previous term and get next term. Example of Fibonacci Series is; 0 1 1 2 3 5.

```
<?php
function printFibonacci($n)
{
$first = 0;
$second = 1;
echo "Fibonacci Series \n";
echo $first.' '.$second.' ';
for($i = 2; $i < $n; $i++){
$third = $first + $second;
echo $third.' ';
$first = $second;
$second = $third;
}
}
/* Function call to print Fibonacci series upto 6 numbers. */
printFibonacci(6);
?>
```

## Reverse number Program in PHP

strrev() function is used to reverse any given number in php, but here we perform this operation without using strrev() function and using strrev() function.

*Reverse number without using library function Program in PHP*

```
<?php
$num = 2039;
$revnum = 0;
while ($num != 0)
{
$revnum = $revnum * 10 + $num % 10;
//below cast is essential to round remainder towards zero
$num = (int)($num / 10);
}
echo "Reverse number: $revnum";
?>
```

*Reverse number Program in PHP*

```
<?php
function reverse_number($number)
{
/* Typecast the number into string. */
$snum = (string) $number;
/* Reverse the string. */
$revstr = strrev($snum);
/* Typecast string into int. */
$reverse = (int) $revstr;
return $reverse;
}
echo reverse_number(2039);
?>
```

## Reverse String Program in PHP

strrev() function is used to reverse any given string in php, but here we perform this operation without using strrev() function.

*Reverse String Program in PHP*

```
<?php
$string = "hitesh";
$length = strlen($string);
for ($i=($length-1) ; $i >= 0 ; $i--)
{
echo $string[$i];
}
?>
```