im having this error : im a beginner and also a diploma student... i have created database using localhost... im having problem viewing my database... please help me... i hope u can help me with a full code... this is the ERROR...

    Warning: mysqli_select_db() expects exactly 2 parameters, 1 given in C:\xampp\htdocs\SLR\View S110 PC01.php on line 10
    cannot select DB

this is my code...

    <?php
    $host="localhost"; // Host name 
    $username="root"; // Mysql username 
    $password=""; // Mysql password 
    $db_name="slr"; // Database name 
    $tbl_name="s110_pc01"; // Table name 
    
    // Connect to server and select databse.
    mysqli_connect("$host", "$username", "$password")or die("cannot connect"); 
    mysqli_select_db("$db_name")or die("cannot select DB");
    
    $sql="SELECT * FROM $tbl_name";
    $result=mysqli_query($sql);
    
    $count=mysqli_num_rows($result);
    ?>
    
    <table width="400" border="0" cellspacing="1" cellpadding="0">
    <tr>
    <td><form name="form1" method="post" action="">
    <table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
    <tr>
    <td bgcolor="#FFFFFF">&nbsp;</td>
    <td colspan="4" bgcolor="#FFFFFF"><strong>Delete multiple rows in mysql</strong> </td>
    </tr>
    <tr>
    <td align="center" bgcolor="#FFFFFF">#</td>
    <td align="center" bgcolor="#FFFFFF"><strong>Software ID</strong></td>
    <td align="center" bgcolor="#FFFFFF"><strong>Software Name</strong></td>
    <td align="center" bgcolor="#FFFFFF"><strong>Installed Date</strong></td>
    <td align="center" bgcolor="#FFFFFF"><strong>Expiry Date</strong></td>
    <td align="center" bgcolor="#FFFFFF"><strong>Product Key</strong></td>
    </tr>
    
    <?php
    while($rows=mysqli_fetch_array($result)){
    ?>
    
    <tr>
    <td align="center" bgcolor="#FFFFFF"><input name="checkbox[]" type="checkbox" id="checkbox[]" value="<? echo $rows['id']; ?>"></td>
    <td bgcolor="#FFFFFF"><? echo $rows['soft_id']; ?></td>
    <td bgcolor="#FFFFFF"><? echo $rows['soft_name']; ?></td>
    <td bgcolor="#FFFFFF"><? echo $rows['installed_date']; ?></td>
    <td bgcolor="#FFFFFF"><? echo $rows['expiry_date']; ?></td>
    <td bgcolor="#FFFFFF"><? echo $rows['product_key']; ?></td>
    </tr>
    
    <?php
    }
    ?>
    
    <tr>
    <td colspan="5" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" id="delete" value="Delete"></td>
    </tr>
    
    <?php
    
    // Check if delete button active, start this 
    if($delete){
    for($i=0;$i<$count;$i++){
    $del_id = $checkbox[$i];
    $sql = "DELETE FROM $tbl_name WHERE soft_id='$soft_id'";
    $result = mysqli_query($sql);
    }
    // if successful redirect to delete_multiple.php 
    if($result){
    echo "<meta http-equiv=\"refresh\" content=\"0;URL=View S110 PC01.php\">";
    }
    }
    mysqli_close();
    ?>
    
    </table>
    </form>
    </td>
    </tr>
    </table>