Update user profile page with PHP MySQL - php

Question

I have created a social website, so far everything is good with the loggin and logout etc... but when it comes to the edit profile page I cant figure out my error can somebody suggest whats wrong or is there a better way to approach this Update Profile page.
The error I am getting is:
Parse error: syntax error, unexpected '$firstname' (T_VARIABLE) in C:\wamp\www\change.php on line 28
My PHP code:
<?php
session_start();
if (isset($_SESSION['username'])) {
$username = $_SESSION['username'];
}
else {
echo "You have not signed in";
}
?>
<?php
include_once ("php_includes/db_conx.php");
$sql = "SELECT * FROM users WHERE username='$u' AND activated='1' LIMIT 1";
$user_query = mysqli_query($db_conx, $sql);
while ($row = mysqli_fetch_array($user_query, MYSQLI_ASSOC)) {
$username = $row["surname"];
$firstname = $row["firstname"];
$surname = $row["surname"];
$weight = $row["weight"];
$height = $row["height"];
}
function filter($date)
{
return trim(htmlspecialchars($date));
}
$username = filter($_POST['username'])
$firstname = filter($_POST['firstname'])
$surname = filter($_POST['surname'])
$weight = filter($_POST['weight'])
$height = filter($_POST['height'])
if (username)
{
$sql = mysql_query ("UPDATE users SET username='$username', firstname='$firstname', surname='$surname', weight='$weight', height='$height' WHERE username='$username'")
or die (mysql_error());
}
?>
<form action="change.php" method="post">
Username: <input type="text" name="username"><br />
Firstname: <input type="text" name="firstname"><br />
Surname: <input type="text" name="surname"><br />
weight: <input type="text" name="weight"><br />
height: <input type="text" name="height"><br />
<input type="submit" value="Submit">
</form>

Answer 1

$username = filter($_POST['username']);
$firstname = filter($_POST['firstname']);
$surname = filter($_POST['surname']);
$weight = filter($_POST['weight']);
$height = filter($_POST['height']);
You need to terminate each statement/ line with ;

Answer 2

$sql = mysql_query ("UPDATE users SET weight='$weight', height='$height' WHERE username='$username'")
i think you have to create like this
$sql = mysql_query ('UPDATE users SET username ="'.$username.'" WHERE username="'.$username.'"');
$sql = mysql_query ('UPDATE users SET firstname="'.$firstname.'" WHERE username = "'.$username.'"');
$sql = mysql_query ('UPDATE users SET surname="'.$surname.'" WHERE username = "'.$username.'"');
$sql = mysql_query ('UPDATE users SET weight='".$weight."' WHERE username = "'.$username.'"');
$sql = mysql_query ('UPDATE users SET height="'.$height.'" WHERE username="'.$username'"');
paste this codes.

Answer 3

You need to terminate each line of code with a semicolon. Line 27 (and the next four lines) are missing the semicolon.