I have this exercise that I am struggling to comprehend the logic to achieve the outcome when qty
is more than 3:
An application to calculate the price of pizzas (listed below) that will be purchased during a promotional period. The number of pizzas will be entered by the user.
- One large pizza will cost $6.45.
- Two large pizzas will cost $12.00.
- Three large pizzas will cost $14.00.
- Four or more pizzas will use a combination of the above prices to ensure the best price for the customer. For example, the best price for five pizzas would be two pizzas ($12.00) + three pizzas ($14.00).
The algorithm must also take account of all possible situations by using sequence, selection and iteration structures.
Below is my code so far:
let calcOrder = () => {
// get inputs
var qty = document.getElementById("quantity").value;
var price = 6.45;
var price2 = 12.0;
var price3 = 14.0;
var totalPrice;
// validate missing, non-digit, negative inputs
if (qty == "") {
document.getElementById("message").innerHTML = "Missing input";
} else if (isNaN(qty)) {
document.getElementById("message").innerHTML = "Numbers only";
} else if (qty < 0) {
document.getElementById("message").innerHTML =
"Negative numbers are not allowed";
} else {
//calc total
if (qty == 1)
{
totalPrice = price;
}
else if (qty == 2)
{
totalPrice = price2;
}
else if (qty == 3)
{
totalPrice = price3;
}
//output total
document.getElementById("message").innerHTML =
`Total price is $${totalPrice}`;
}
// prevent form from submission
return false;
};
Thank you
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