function addition( $x = 10 ){  
	echo $x + 10;  
}  
addition(40); // outputs :  50
addition(); // passing no value. outputs :  20function addition( $x = 10, $y = 20 ){  
	echo $x + $y;  
}  
addition(5); // passing one argument. outputs :  25
addition(); // passing no value. outputs :  30function print_arr(...$numbers) {  
    foreach ($numbers as $element) {  
        echo $element."\n";  
    }  
}  
echo print_arr(1, 2, 3, 4);  
// outputs :   1 2 3 4function display( $number ) {    
    if( $number <= 10 ){    
     echo "$number";    
     display ($number+1 );    
    }
}    
display(0);  
// outputs :  012345678910$bool = TRUE;  
if (is_null($bool))  
{
	echo 'Variable is  NULL';  
}
else 
{
	echo 'Variable is not NULL';  
}  
// outputs :  Variable is not NULL
$x = 5;  
$y = 10;  
// Swapping Logic  
$temp = $x;  
$x = $y;  
$y = $temp;  
echo "After swapping: ";  
echo "\n x = $x \n y = $y";  
// outputs :  x = 10   y = 5$x = 5;  
$y = 10;  
$x = $x + $y;  // 15
$y = $x - $y;  // 5
$x = $x - $y;  // 10
echo "After swapping: ";  
echo "\n x = $x \n y = $y";  
// outputs :  x = 10   y = 5$x = 5;  
$y = 10;  
$x = $x*$y;  // 50
$y = $x/$y;  // 5
$x = $x/$y;  // 10
echo "After swapping: ";  
echo "\n x = $x \n y = $y";  
// outputs :  x = 10   y = 5rand();rand(min,max);$x = rand(0,10);
echo $x;
// outputs :  random integer between 0 and 10 (inclusive)$num = 0;  
$n1 = 0;  
$n2 = 1;  
echo "Fibonacci series for first 20 numbers: \n";  
echo $n1.' '.$n2.' ';  
while ( $num < 18 )  
{  
    $n3 = $n2 + $n1;  
    echo $n3.' ';  
    $n1 = $n2;  
    $n2 = $n3;  
    $num = $num + 1;  
}
// 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 range(low, high, step) 
// third parameter is optional, Specifies the increment used in the range. Default is 1// Return an array of elements from "0" to "20".increment by 5.
$number = range(0,20,5);
print_r ($number);
// outputs :  0 5 10 15 20
// Using letters - return an array of elements from "a" to "k"
$letter = range("a","k");
print_r ($letter);
// outputs :  a b c d e f g h i j k
$alpha = range('A', 'Z');  
for( $i = 0; $i < 10; $i++ ) {   
  for( $k = 10; $k > $i ; $k-- ){  
    echo $alpha[$i];  
    }  
    echo "\n";  
}  AAAAAAAAAA
BBBBBBBBB
CCCCCCCC
DDDDDDD
EEEEEE
FFFFF
GGGG
HHH
II
J$int = 10;
echo "I.  Value of \$int is:  $int\n";
echo gettype("$int"); // outputs :  string$int = 10;
echo "II. Value of \$int is:  ".$int;