PHP : Condition statement

$a = 1; $b = 2; /* if */ if ($a > $b)          echo "a is greater than b"; /* else */ if ($a > $b) {          echo "a is greater than b"; } else {          echo "a is NOT greater than b"; } /* elseif */ if ($a > $b) {          echo "a is greater than b"; } elseif ($a == $b) {          echo "a is equal to b"; } else {          echo "a is less than b"; } /* switch */ switch ($i) {          case 0:                   echo "i equals 0";                   break;          case 1:                   echo "i equals 1";                   break; case 2:                  echo "i equals 2";                  break; }