Please check this
<?php
session_start();
ob_start();
$conn = mysqli_connect("localhost","root","","hct_db");
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$username=$_POST['username'];
$password=$_POST['password'];
$username = stripslashes($username);
$password = stripslashes($password);
$username = mysqli_real_escape_string($conn, $username);
$password = mysqli_real_escape_string($conn, $password);
$sql="SELECT username, password FROM admin where username='".$username."' and password='".$password."'";
$result=mysqli_query($conn,$sql);
$count=mysqli_num_rows($result);
if($count==1){
session_register("username");
session_register("password");
header("location:admin/index.php");
}
else {
echo "Wrong Username or Password";
}
ob_end_flush();
?>