Online PHP editor | output for H3DoQ

<?php $int_var=256; $double=2.54; $r=$int_var+$double; echo"$r"; if(2+1==4) { echo"this value is equal"; } else { echo"this value is not equal\n"; } define("constant",80); echo constant("constant"); $a=10; $b=200; echo "$a + $b, this is arithmetic operation\n"; echo "$b - $a , this is subtraction operation\n"; echo "$b / $a , this is division operation\n"; echo "$b % $a, this is modulus and returns reminder\n"; echo "$a * $b, this is multipication\n"; echo "++$a, this will increment a value and return a value\n"; echo "$a++, this will first print a value then it increment\n"; echo "$--$b, this will decrement b value and return b \n"; echo "$b--, this will return b value and then decrement\n";