Parse error with two codes

Question

<?php

include 'core/init.php';

if (empty($_POST) === false) 
{
    $username= $_POST ['username'];
    $password= $_POST ['password'];

    if (empty($username) === true || (empty($password) === true)
{
   echo "Write your User name and Password"  ;

}else if (user_exists($username) === false) {

 echo =   "Username does not exists. Have you registered?";
}

}
?>

Parse error: syntax error, unexpected 'echo' (T_ECHO) in C:\xampp\htdocs\login.php on line 12

or even

<?php

include 'core/init.php';

if (empty($_POST) === false) 
{
    $username= $_POST ['username'];
    $password= $_POST ['password'];

    if (empty($username) === true || (empty($password) === true)
{
  $errors =  "Write your User name and Password"  ;

}else if (user_exists($username) === false) {

 $errors=   "Username does not exists. Have you registered?";
}

}
?>

Parse error: syntax error, unexpected ';' in C:\xampp\htdocs\login.php on line 12