Q. PHP Program to Find Gcd of Two Numbers.

Here you will find an algorithm and program in PHP to find GCD of two numbers. First let us understand what is GCD.

Explanation : GCD stands for Greatest Common Divisor, GCD of two numbers is the largest number that can exactly divide both numbers. It is also called as HCF.

For Example : GCD of 60 and 45 is 15. 15 is the greatest number which can divide both 60 and 45. Therefore GCD of 60 and 45 is 15.

START
1. Input 2 Numbers A and B and declare variable GCD which holds the result.
2. Run Loop i from 1 to i <= A and i <=B
    Check if A & B are completely divisible by i or not if yes then
         Assign GCD = i
    Loop End
3. Output GCD 
STOP

PHP Program to Find Gcd of Two Numbers

function find_gcd($num1, $num2) 
{ 
  // Everything divides 0  
  if ($num1 == 0) 
    return $num2; 
  if ($num2 == 0) 
    return $num1; 
  // base case 
  if($num1 == $num2) 
    return $num1 ; 
  // a is greater 
  if($num1 > $num2) 
    return find_gcd( $num1-$num2 , $num2 ) ; 
    return find_gcd( $num1 , $num2-$num1 ) ; 
}

$num1 =  60;
$num2 = 45; 
echo "GCD of $num1 and $num2 is ", find_gcd($num1 , $num2) ; 

Output

GCD of 60 and 45 is 15