Ive got this error and i dont know how to get rid of it, could someone please help the error is.

Warning: preg_match() [function.preg-match]: No ending delimiter '/' found in M:\EasyPHP-5.3.5.0\www\clac2.php on line 101

code is attached

<?php// Defining the "calc" classclass calc {var $number1;var $number2;function add($number1,$number2){$result =$number1 + $number2;echo "The sum of $number1 and $number2 is $result<br><br>";echo "$number1 + $number2 = $result";exit;}function subtract($number1,$number2){$result =$number1 - $number2;echo "The difference of $number1 and $number2 is $result<br><br>";echo "$number1 - $number2 = $result";exit;}function divide($number1,$number2){$result =$number1 / $number2;echo "$number1 divided by $number2 is $result<br><br>";echo "$number1 ? $number2 = $result";exit;}function multiply($number1,$number2){$result =$number1 * $number2;echo "The product of $number1 and $number2 is $result<br><br>";echo "$number1 x $number2 = $result";exit;}function square($number){$result = $number * $number;echo "The square of $number is $result<br><br>";echo "$number ^ 2 = $result";}function squareroot($number){$result = sqrt($number);echo "The square root of $number is $result<br><br>";}function cube($number){$result = $number * $number * $number;echo "The cube of $number is $result<br><br>";echo "$number1 ^ 3 = $result";}}//Creating object of class$calc = new calc();?><title>PHP Calculator </title><h2>Calculator 1</h2><form name="calc" action="" method="POST">Number 1: <input type="text" name="value1"><br>Number 2: <input type="text" name="value2"><br>Operation:<select name="oper"><option value="add">Addition</option><option value="subtract">Subtraction</option><option value="divide">Division</option><option value="multiply">Multiplication</option></select><br><input type="submit" value="Calculate" name="submit"></form><br><br><h2>Calculator 2</h2><form name="calc2" action="" method="POST">Number : <input type="text" name="value"><br>Operation:<select name="operat"><option value="square">Square</option><option value="squareroot">Square Root</option><option value="Cube">Cube</option></select><br><input type="submit" value="Calculate" name="submit1"></form><?phpif($_POST['submit']){$number1 = $_POST['value1'];$number2 = $_POST['value2'];$oper = $_POST['oper'];if(!$number1){echo "<font color='red'>Please enter first number in calculator 1</font>";exit;}if(!$number2){echo "<font color='red'>Please enter second number in calculator 1</font>";exit;}if(!$oper){echo "<font color='red'>Please select operator in calculator 1</font>";exit;}if(!preg_match("/^-?(0|[1-9]\d*)(\.\d+)?$", $number1)){echo "<p style='color: red'>The entry for number 1 was not a number</p>";exit;}if(!preg_match("/^-?(0|[1-9]\d*)(\.\d+)?$", $number2)){echo "<p style='color: red'>The entry for number 2 was not a number</p>";exit;}if($oper == "add"){$calc->add($number1,$number2);}if($oper == "subtract"){$calc->subtract($number1,$number2);}if($oper == "divide"){$calc->divide($number1,$number2);}if($oper == "multiply"){$calc->multiply($number1,$number2);}}?><?phpif($_POST['submit1']){$number = $_POST['value'];$operat = $_POST['operat'];if(!$number){echo "<font color='red'>Please enter number in calculator 2</font>";exit;}if(!$operat){echo "<font color='red'>Please select operator in calculator 2</font>";exit;}if(!eregi("[0-9]", $number)){echo "<font color='red'>Value must be digits in calculator 2</font>";exit;}if($operat == "square"){$calc->square($number);}if($operat == "cube"){$calc->cube($number);}if($operat == "squareroot"){$calc->squareroot($number);}}?>

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Line 105: if(!preg_match("/^-?(0|[1-