diff --git a/mathexphtml.php b/MathExpHtml.php
similarity index 67%
rename from mathexphtml.php
rename to MathExpHtml.php
index 1aa3448..0de174c 100644
--- a/mathexphtml.php
+++ b/MathExpHtml.php
@@ -1,19 +1,19 @@
 <?php
 
-/******
- * mathExpHtml Class
- *
+/**
+ * MathExpHtml Class
+ * 
  * This class is free for the educational use as long as maintain this header together with this class.
  * Author: Win Aung Cho
  * Contact winaungcho@gmail.com
  * version 1.0
  * Date: 26-11-2022
- *
- ******/
-class mathExpHtml
+ */
+class MathExpHtml
 {
     private $tokens;
-    function __construct($str)
+
+    public function __construct($str)
     {
         define('_OPERATORS', array(
             '(',
@@ -28,251 +28,241 @@ function __construct($str)
             '>',
             ','
         ));
+
         $this->tokens = $this->str2tokens($str);
     }
-    function operators()
+
+    public function printTokens()
+    {
+        echo "<pre>";
+        foreach ($this->tokens as $token) {
+            $token = trim($token);
+            echo $token . "  is " . $this->tokentype($token) . "<br/>";
+        }
+        echo "<br/></pre>";
+    }
+
+    public function gethtml()
+    {
+        $tokens = $this->parsepar($this->tokens);
+        echo "" . $this->exphtml($tokens) . "";
+    }
+
+    private function operators()
     {
         return _OPERATORS;
     }
-    function str2tokens($str)
+
+    private function str2tokens($str)
     {
         $tokens = preg_split('/([<>()*\/=^+-])\s*|([\d.]+)\s*|(\w+)\s*|({\w+})\s*/', $str, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+
         return $tokens;
     }
-    function tokentype($token)
+
+    private function tokentype($token)
     {
         return (is_numeric($token) ? "value" : (in_array($token, _OPERATORS) ? "operator" : (preg_match('/^[\w-]+$/', $token) ? "alphanum" : 
         	(preg_match('/({\w+})/', $token)?"vector":"none"))));
     }
-    function mathhtml($a, $o, $b)
+
+    private function mathhtml($a, $o, $b)
     {
         $html = "";
+
         switch ($o)
         {
             case '+':
             case '-':
-            
             case '=':
             case '<':
             case '>':
             case ',':
                 $html = "$a $o $b";
-            break;
+                break;
+
             case '*':
-            $html = "$a • $b";
-            break;
+                $html = "$a • $b";
+                break;
+
             case '^':
                 $html = "$a<sup>$b</sup>";
-            break;
+                break;
+
             case '/':
                 $html = "<div class=\"fraction\">";
                 $html .= "<span class=\"numer\">$a</span>"; // numerator
                 $html .= "<span class=\"bar\">/</span>";
                 $html .= "<span class=\"denom\">$b</span>"; // denominator
                 $html .= "</div>";
-            break;
+                break;
         }
+
         return ($html);
     }
-    function testknownoperator($token){
+
+    private function testknownoperator($token) 
+    {
     	$pattern = "/([(),+])\s*/";
-    	//$str = strip_tags($token);
     	$test = preg_split($pattern, $token, 8, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
-    	
-    	//echo "<br/>";
-    	//print_r($test);
-    	//echo "<br/>";
-    	
     	$html = "";
-    	
     	if (strip_tags($test[0]) == 'sum'){
     		$html = "<span class=\"intsuma\">".
     		"<span class=\"lim\">".$test[4]."</span>".
     		"<span class=\"sum-frac\">&sum;</span>".
     		"<span class=\"lim\">".$test[2]."</span>".
     		"</span>";
-    	}/*
-    	 else if (strip_tags($test[0]) == 'int'){
-    		$html = "<span class=\"intsuma\">".
-    		"<span class=\"lim\">".$test[4]."</span>".
-    		"<span class=\"sum-frac\">&int;</span>".
-    		"<span class=\"lim\">".$test[2]."</span>".
-    		"</span>";
     	}
-    	*/
+
     	return $html;
     }
-    function formatelement($tokens)
+
+    private function formatelement($tokens) 
     {
         $len = count($tokens);
-        for ($i = 0;$i < $len;$i++)
-        {
+        for ($i = 0;$i < $len;$i++) {
             $a = $tokens[$i];
             $b = ($i < $len - 1) ? trim($tokens[$i + 1]) : " ";
-            if ($this->tokentype($a) == "alphanum")
-            {
-                if ($b[0] == '('){
+
+            if ($this->tokentype($a) == "alphanum") {
+                if ($b[0] == '(') {
                 	$a = "<span style='color:green;'><var>$a</var></span>";
+                } else {
+                    $a = "<var>$a</var>";
                 }
-                else $a = "<var>$a</var>";
-            }
-            else if ($this->tokentype($a) == "value"){
+            } elseif ($this->tokentype($a) == "value") {
             	$a = "<span style='color:blue;'>$a</span>";
-            } else if ($this->tokentype($a) == "vector"){
+            } elseif ($this->tokentype($a) == "vector") {
             	$a = str_replace(array("{", "}"), "", $a);
             	$s = strlen($a);
             	$a = " <span class=\"sym\"><var>$a</var>".
             		"<span class=\"vec\" style=\"transform:scale($s,1.0);\">&rarr;</span>".
             		"</span>";
             }
+
             $tokens[$i] = $a;
         }
+
         return $tokens;
     }
     
-    function parsepar($tokens)
+    private function parsepar($tokens)
     {
         $tokens = $this->formatelement($tokens);
         $pos = 0;
         $len = count($tokens);
         $level = 0;
-        while ($pos < $len)
-        {
+        while ($pos < $len) {
             $a = $tokens[$pos];
-            while ($a != "(" && $pos < $len)
-            {
+
+            while ($a != "(" && $pos < $len) {
                 $pos++;
                 $a = $tokens[$pos];
             }
-            while ($a != ")" && $pos < $len)
-            {
-                if ($a == "(")
-                {
+
+            while ($a != ")" && $pos < $len) {
+                if ($a == "(") {
                     $start = $pos;
                     $level++;
                 }
+
                 $pos++;
                 $a = $tokens[$pos];
             }
-            if ($a == ")")
-            {
+
+            if ($a == ")") {
                 $end = $pos;
                 $level--;
                 $subtokens = array_slice($tokens, $start + 1, $end - $start - 1);
                 array_splice($tokens, $start + 1, $end - $start);
                 $tokens[$start] = "(" . $this->exphtml($subtokens) . ")";
-                //echo "sub ".$subtokens[0]."=>".count($subtokens)."<br/>";
                 $pos = $start;
             }
+
             $pos++;
         }
-        /*
-        print_r($tokens);
-        echo "<br/>";
-        print_r($subtokens);
-        echo "<br/>";
-        echo "level ".$level."<br/>";
-        */
-        if ($level != 0) $tokens = $this->parsepar($tokens);
+
+        if ($level != 0) {
+            $tokens = $this->parsepar($tokens);
+        }
+
         return $tokens;
     }
-    function exphtml($tokens)
+
+    private function exphtml($tokens)
     {
         $len = count($tokens);
         
-        if ($len <= 2)
-        {
+        if ($len <= 2) {
             return $tokens[0];
         }
-        // merge function
-        for ($i = 0;$i < $len;$i++)
-        {
+
+        for ($i = 0;$i < $len;$i++) {
             $a = $tokens[$i];
             $b = ($i < $len - 1) ? trim($tokens[$i + 1]) : " ";
-            if ($this->tokentype(strip_tags($a)) == "alphanum")
-            {
-                if ($b[0] == '('){
+            if ($this->tokentype(strip_tags($a)) == "alphanum") {
+                if ($b[0] == '(') {
                 	$tokens[$i] = $a . $b;
                 	array_splice($tokens, $i + 1, 1);
                 	$html = $this->testknownoperator($tokens[$i]);
-                	if ($html != "") $tokens[$i] = $html;
+                	if ($html != "") {
+                        $tokens[$i] = $html;
+                    }
                 }
             }
         }
+
         $len = count($tokens);
-        //echo "length ".$len."<br/>";
         $pos = 0;
-        while ($pos < $len - 2)
-        {
+        while ($pos < $len - 2) {
             $a = $tokens[$pos];
             $o = $tokens[$pos + 1];
             $b = $tokens[$pos + 2];
 
-            if ($this->tokentype($o) == "operator" && $o == '^')
-            {
+            if ($this->tokentype($o) == "operator" && $o == '^') {
                 $a = $this->mathhtml($a, $o, $b);
                 $tokens[$pos] = $a;
                 array_splice($tokens, $pos + 1, 2);
                 $len = count($tokens);
+            } else {
+                $pos += 2;
             }
-            else $pos += 2;
         }
 
         $pos = 0;
-        while ($pos < $len - 2)
-        {
+        while ($pos < $len - 2) {
             $a = $tokens[$pos];
             $o = $tokens[$pos + 1];
             $b = $tokens[$pos + 2];
 
-            if ($this->tokentype($o) == "operator" && ($o == "/" || $o == "*"))
-            {
+            if ($this->tokentype($o) == "operator" && ($o == "/" || $o == "*")) {
                 $a = $this->mathhtml($a, $o, $b);
                 $tokens[$pos] = $a;
                 array_splice($tokens, $pos + 1, 2);
                 $len = count($tokens);
             }
-            else $pos += 2;
+            else {
+                $pos += 2;
+            }
         }
 
         $pos = 0;
         $a = $tokens[$pos];
-        while ($pos < $len - 2)
-        {
+        while ($pos < $len - 2) {
             $o = $tokens[$pos + 1];
             $b = $tokens[$pos + 2];
             
-            if ($this->tokentype($o) == "operator")
-            {
+            if ($this->tokentype($o) == "operator") {
                 $a = $this->mathhtml($a, $o, $b);
             }
+
             $pos += 2;
         }
+
         if ($pos < $len-1 && $tokens[$pos+1][0] == '(') {
         	$a .= $tokens[$pos+1];
         }
         
         return $a;
     }
-    function printtokens()
-    {
-        echo "<pre>";
-        foreach ($this->tokens as $token)
-        {
-            $token = trim($token);
-            echo $token . "  is " . $this->tokentype($token) . "<br/>";
-        }
-        echo "</pre>";
-        echo "<br/>";
-    }
-    function gethtml()
-    {
-        $tokens = $this->parsepar($this->tokens);
-        //echo "<br/>";
-        //print_r($tokens);
-        //echo "<br/>";
-        echo "" . $this->exphtml($tokens) . "";
-    }
 }
-
-?>
diff --git a/README.md b/README.md
index a9c78ba..c30e5af 100644
--- a/README.md
+++ b/README.md
@@ -1,26 +1,44 @@
-![Math-Expression-to-HTML](mathexphtml.jpg)
 # Math-Expression-to-HTML
-Produce html code from the mathematic expression string
 
-## Check Demo
-Visit following link and check demo in forum.
-[Demo](https://edu.structsoftlab.com/forum/)
+Produce html code from the mathematic expression string.
+![Math-Expression-to-HTML](mathexphtml.jpg)
+
+## Demo version
+
+Visit following link and check demo in forum
+[Demo](https://edu.structsoftlab.com/forum/).
+
+## Usage
+
+First include the `MathExpHtml.php` class in your file, and use the class as following to generate the HTML for the math expressions:
+
+```php
+$expression = "a=sum(i=1,3)(23.5*{vec}-(((cos(2+θ/2)+asd9)^2)/4.5+sin(0.5*θ))/(20.06+π*(16))^2-26)";
+
+$parser = new MathExpHtml($expression);
+$parser->printTokens();
+$parser->gethtml();
+```
 
 ## Features
-Algorythm is very simple.
-- String is tokenized using preg_split into array of tokens, 
+
+Algorithm is very simple.
+
+- String is tokenized using `preg_split` into array of tokens, 
 - Token types are value, alpha-numeric and operator.
 - Alpha numeric represents as a variable or function name.
 - There are some known functions such as summation sign sum(i=1, 5).
 - First tokens are simplify into simple expression inside the parenthesis.
-- Nested parenthesis are alliwed.
+- Nested parenthesis are allowed.
 - Simple inside () are convert into html code using predefined css classes.
 - Precedence are common as following order, ^, *,/,+.-.
-- Multiple expressions of () may connected without operator, 
--  eg., (3+a/4)(sin(0.5*θ))
-- Vector variable can be used in written form enclosed with cali-bracket.
--  eg., {vec}
+- Multiple expressions of () may connected without operator eg., (3+a/4)(sin(0.5*θ))
+- Vector variable can be used in written form enclosed with cali-bracket eg., {vec}.
+
+## Licence
+
+This project is published under the Gnu General Public License see [the License File](LICENSE) for more information.
 
 ## Contact
-Contact me for comercial use via mail winaungcho@gmail.com
 
+Contact me for comercial use via mail winaungcho@gmail.com.
diff --git a/example.php b/example.php
index 72579c3..ef6f147 100644
--- a/example.php
+++ b/example.php
@@ -1,19 +1,20 @@
 <?php
-include("mathexphtml.php");
 
-/******
- * mathExpHtml Class and example file
+/**
+ * MathExpHtml Class and example file
  *
  * This class is free for the educational use as long as maintain this header together with this class.
  * Author: Win Aung Cho
  * Contact winaungcho@gmail.com
  * version 1.0
  * Date: 26-11-2022
- *
- ******/
+ */
+
+include("MathExpHtml.php");
+
 ?>
 
-<html>
+<html lang="en">
 	<head>
 		<meta charset="utf-8">
 		<style>
@@ -98,9 +99,8 @@
 		<div style="overflow-x:auto;overflow-y:auto; width:100%;height:100%;white-space: nowrap;">
 			<?php
 				$str = "a=sum(i=1,3)(23.5*{vec}-(((cos(2+θ/2)+asd9)^2)/4.5+sin(0.5*θ))/(20.06+π*(16))^2-26)";
-				$parser = new mathExpHtml($str);
-
-				$parser->printtokens();
+				$parser = new MathExpHtml($str);
+				$parser->printTokens();
 				$parser->gethtml();
 			?>
 		</div>