POS Software System Using C (Part 1)

This project is made for my C Programming subject in Informatics. The project is a simple POS (Point of Sale) system  implemented using the C Program. The software is supposedly used for a fictitious drugstore company in their quest for a better and efficient store system.

I will be separating this into separate articles since it will be too long for a single reading and I'm afraid you may get bored easily.  I will begin the discussion on the current system of this company and the new and improved system using the POS software.Then the software's initial screen designs (user interface) and input specifications will be discussed. In the next article, I will be discussing some of the C programming codes on how I've accomplished the user interface and the logic behind the software.


Chapter 1. Analysis and Design

1.1 Current System

ABC Drugstore Company is a medium-scale drugstore located in Colon, Cebu. Its employees include the Cashier that handles cash transactions, Inventory clerks that handle Inventory Management, Sales Persons that handle customer transactions and an Administrator that supervises the operation of the company.

With its steadily growing number of products in their inventory, it is becoming more difficult for its Sales Persons to remember all the product details. The Sales Persons can only remember those products that are common. When a customer asks if a particular product is available, most of the time they have to rely on their resident pharmacist to provide them answers. However, other sales persons don’t bother to inquire and simply say that the item is unavailable. The management are aware of this problem and they are looking for a software solution to provide Query capabilities that can be used by their Sales Persons.

To achieve this, their Inventory System has to be upgraded also. Currently, they use inventory books to list all products that are available and to record its stock quantity and prices. To update these items, the inventory clerks have a big task of searching for the particular record through the big volumes of inventory books. Sometimes, the records are misplaced making it more difficult to update records. Sometimes, duplicate records are created, creating confusions and more mistakes.
Last but not the least of the improvements that need to be done is the cash register. Believe it or not, the cashier still uses this plain old but reliable calculator to compute the total amount purchased. According to the cashier, there are cases that products have wrong price labels. Since her only way of knowing the prices is through the labels, there’s no way to check for this kind of problem. Also, the cashier has to create a list of products purchased so the inventory clerk can manually update the inventory’s stock quantity records. Discrepancy of stock quantity can occur because of this manual updating.

1.2 New System

I was contacted by Management to provide effective solutions to their various problems. Instead of creating separate programs for each problem, it was decided to use an all in one system that can provide all the solution to the problem in a single program. Thus, the POS Software system was created.

To solve the problems of the sales people, the new system has to have a Query System that is capable of searching for a particular product. It must be capable of searching the product by its name or by its maker or by its description. All the sales people need to do is to input the product’s name/maker/description, and then the software shall automatically display all products that matched the search. The search results must display all details of the product.
To solve the problem of the inventory clerks, the record books has to be discarded and replaced with a software database system where products can be electronically added, edited or deleted. Because it software based, it will now be easy to update and search records. Automatic checking will be put in place to prevent duplicate records. Besides, waste in paper resources will be reduced.

To solve the problem of the cashier, the calculator has to go. It must be replaced with a POS system that will be capable of displaying purchased items’ details specially the product’s price. This way, the cashiers can double check the price label if it is accurate. To operate the POS terminal, the cashier needs to input only the barcode and quantity of the product and then the software will automatically calculate the total amount of purchased items. This will reduce the common mistakes associated with using calculator. Also, the software will automatically update the stock quantity of the products, once purchase transaction is done. This will eliminate the need for manual updating of the stock quantity and reduce discrepancy in the quantities.

The software must also have a security access system in place to prevent unauthorized access to the program. Also, the program must have different restrictions for each type of employee. This will prevent employees from accessing the features of the program that they are not allowed to do. For example, the inventory clerks must not be allowed access to the POS terminal. And in the same way, the cashier must not be allowed access to the database of products.

1.3 Program Specification

        1.3.1 Screen Design and Input Specification

The login form is used for accessing the software. The user needs to input his username and password, which must be at most 14 ASCII characters.

The change password form is used for changing the user's password. The user needs to input the new password and confirmation password, which must be at most 14 ASCII characters.

The main menu form is used to access the different features of the system. The user only needs to select the desired menu using the arrow keys.

The User Account Form is used to select which actions the user needs in the account menu. The user only needs to select the desired menu using the arrow keys.

The Add Account Form is used to add user accounts. The user needs to input the following:
First Name: at most 14 ASCII characters
Last Name: at most 14 ASCII characters
User Name: at most 14 ASCII characters
Password:  at most 14 ASCII characters
Type: select type using arrow keys
Policy: select policy using arrow keys

The Delete Account Form is used to delete accounts. The user  can browse to a particular account using the navigation menu or he can enter a string (at most 14 ASCII characters) to search for a particular account .

The Edit Account Form is used to edit the account data. Refer to the Add Account form for the required data.

TheProduct Form is used to select which actions the user needs in the product menu. The user only needs to select the desired menu using the arrow keys.

The Add Product Form is used to add product records. The user needs to input the following:
Product Name: at most 14 ASCII characters
Maker: at most 14 ASCII characters
Description: at most 14 ASCII characters
Barcode:  5 integer characters (0-9)
Price: at most 12 characters (positive decimal)
Quantity: at most 6 charcters (positive integer)

The Delete Product Form is used to delete product records. The user  can browse to a particularproduct using the navigation menu or he can enter a string (at most 14 ASCII characters) to search for a particular product.

The Edit Product Form is used to edit the product records. Refer to the Add Product Form for the required data.

The POS Form is used for inputting purchase transactions. The user needs to input the product barcodes (5 integer characters) and purchase quantity (at most 6 positive integer charcters) .

The Query Form is used for searching for a particular product. The user needs to input the query string (at most 14 characters). Searching can be done by Name or by Maker.

I will be discussing the source codes on how all these are accomplished on Part 2 of this article...