can't seem to connect to msql, local host?

Question 1

Try this:

<?php
  $host = "hostname";
  $user = "username";
  $password = "password";
  $database = "database";

  $link = mysqli_connect($host, $user, $password, $database);
  If (!$link){
      echo ("Unable to connect to database!");
  }
  else {
  $query = "SELECT * FROM Customer";    
  $result = mysqli_query($link,$query);

  while ($row = mysqli_fetch_array($result, MYSQLI_BOTH)){
   echo  $row['<insert column name>']. "<br>";
  }
}
mysqli_close($link);
?>

I have used the MYSQL library in this code. You should check if you column in mysql is called 0 and 1. B.T.W. I am using WHILE instead of FOR loop that is just a personal preference.

Question 2

Here is what you can do to see your error:

mysql_connect('<server is here>','<my username here>','<password here>') 
or die('Error: '.mysql_error() );

And try to refrain from using all functions starting with mysql_*. They are currently being depricated.

Use mysqli or pdo

Question 3

I would suggest you to start using PDO;

index.php

<?php 
require "dbc.php";

$getList = $db->getAllData(25);

foreach ($getList as $key=> $row) {
         echo $row['columnName'] .' key: '. $key;
    }
?>

dbc.php

<?php
class dbc {
public $dbserver = 'server';
public $dbusername = 'user';
public $dbpassword = 'pass';
public $dbname = 'db';

function openDb() {    
    try {
        $db = new PDO('mysql:host=' . $this->dbserver . ';dbname=' . $this->dbname . ';charset=utf8', '' . $this->dbusername . '', '' . $this->dbpassword . '');
    } catch (PDOException $e) {
        die("error, please try again " . $e);
    }        
    return $db;
}

function getAllData($qty) {
    //prepared query to prevent SQL injections
    $query = "Select * from Customer where zip= ?";
    $stmt = $this->openDb()->prepare($query);
    $stmt->bindValue(1, $qty, PDO::PARAM_INT);
    $stmt->execute();
    $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
    return $rows;
}    
?>

Question 4

This is how I usually connect to an MySQL database. I have config.php

<?php

function db_connect(){
   $conn = new mysqli('localhost', 'root', 'leave_black_if_no_password_set', 'database_name');
   if (!$conn) {
      return false;
   }
   $conn->autocommit(TRUE);  
    return $conn;

}

?>

//end config

Now, in your other file just call config.php: `include 'config.php';

    <html>
    <body>
    <?php 
    include 'php/config.php';
    $dbCon = db_connect();


    $sql = "Select * from Customer";
    $result = mysqli_query($dbCon, $sql);
    $number= mysqli_num_rows($result);

   while($row=mysqli_fetch_array($result)){
    {
        echo  $row['column_name'];
        echo '<br>';
    }
//close conn
 mysqli_close($dbCon);
    ?>
        </body>
    </html>