Tips for Coding the Cash Register Project

Coding Flowchart

What follows is a Logical Flow of the PHP code, written in plain English, for the cash register program.

First rename the $_GET or $_POST variables. We do this to make them easier to work with in the code.
- Note: Chkdisc is a special case, because it may be passed as a NULL (does not exist) value. Write code to set the chkdisc to a value > 0 if it is null.
- Use a decimal, not a percent, when setting checkdisc
As of this point, you have 4 variables you are now working with:
- $meal
- $disc_perc (the decimal value, actually, of the discount)
- $tax
- $tip
Next, we use a SWITCH CASE statement to assign the value of the price to the meal. For example, if the meal chosen was SPAGHETTI, set the price to $5 or $14.50 or whatever you choose.
- Note, we are “switching case,” i.e., checking the value of, the variable $meal
Next, we calculate the DOLLAR AMOUNT of the discount, using the value of the $disc_perc that we calculated earlier.
-Note, the discount amount is calculated by multiplying:
$meal * $disc_perc

Next, we use simple math to calculate the BILL
Note: use $bill as the variable for holding the bill amount
Lastly, we print the variables onto the page using the ECHO statement.
- The only catch here is the number format function, which I will show you, to print only two decimal places!