不记得如何在PHP中计算和返回我的值？

Question

Here's my php. i cant remember if i need a return or not. I'm simple trying to take input from a html form and post the information from it and calculate the shipping and tax. i also didn't remember how to use tabs in php so i made my own with $tabthis; .

<?php
    $fname = $_POST["fname"];
    $lname = $_POST["lname"];
    $city = $_POST["city"];
    $province = $_POST["Province"];
    $postal = $_POST["postalcode"];
    $address = $_POST["Address"];
    $tabThis = "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;";
    $semiTabThis = "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;";
    $numberOfPizzas = $_POST["numOfPizza"];
    $sizeOfPizzas = $_POST["sizeOfPiz"];
    $cost = 0;
    $ttProduct = 0;
    $shipping = 0;
    function itemAmountAndTax($cost){

        if($numberOfPizzas == 1){
            $cost = 5.75;
            $ttProduct = $cost;
            return $ttproduct;
        }
        else if($numberOfPizzas == 2){
            $cost = 11.50;
            $ttProduct = $cost;
        }
        else if($numberOfPizzas == 3){
            $cost = 17.25;
            $ttProduct = $cost;
        }
        else if($numberOfPizzas == 4){
            $cost = 23.00;
            return $cost;
            $ttProduct = $cost;
        }
        else if($numberOfPizzas == 5){
            $cost = 28.75;
            $ttProduct = $cost;
        }
        else if($numberOfPizzas == 6){
            $cost = 34.5;
            $ttProduct = $cost;
        }
        else if($numberOfPizzas == 7){
            $cost = 40.25;
            $ttProduct = $cost;
        }
        else if($numberOfPizzas == 8){
            $cost = 46;
            $ttProduct = $cost;
        }
        else if($numberOfPizzas == 9){
            $cost = 51.75;
            $ttProduct = $cost;
        }
    }
    function totalCalculator(){

        if( $ttProduct > 0.00 || $ttProduct <= 25.00)
        {
            $shipping = 3.00;
        }
        else if($ttProduct > 25.01 || $ttProduct < 50.00)
        {
            $shipping = 4.00;
        }   
        else if($ttProduct > 50.01 || $ttProduct < 75.00)
        {
            $shipping = 5.00;
        }
        else if($ttProduct > 75.01)
        {
            $shipping = 6.00;
        }
    }
?>
Shipping To: <?php echo $fname; ","; ?> <?php echo $lname; ?><br>
<?php echo $tabThis; ?><?php echo $address; ?><br>
<?php echo $tabThis; ?><?php echo $city; ?><?php echo "" ?><?php echo $province; ?><br>
<?php echo $tabThis; ?><?php echo $postal; ?><br>
Order Information:<br>
<br>
<?php echo $semiTabThis; ?>Your Order is Being Processed, Please verify the information<br>
<?php echo $tabThis; ?><?php echo $numberOfPizzas; ?> Pizza's at <?php?>itemAmountAndTax($cost); each <br>
<?php echo $tabThis; ?>Tax = <?php?><br>
<?php echo $tabThis; ?>Delivery = <?php?><br>
<?php echo $tabThis; ?>Total Cost's = <?php?><br>

Answer 1

Tabs are denoted by "\t". So

$tabThis = "\t\t\t....";

Why don't you declare the price of one pizza as a constant and pass the number of pizzas to a function which simply multiplies the number of pizzas with the price of one pizza??

define("PRICE_OF_ONE_PIZZA",5.75);

function get_pizza_price($num_pizzas) {
 return $num_pizzas*PRICE_OF_ONE_PIZZA;
}//end function