Payment Application Simulation

This is a Payment Application Simulation project for the EgFWD Embedded Systems Professional NanoDegree Scholarship. This project was written in C. It includes a Luhn card PAN generation and validation.

Program Flow Chart

Functions

These are some of the functions I thought I should highlight:

• appStart() : this would be called in Main.c to start the application
• getTransactionDate() : asks for a date in the form DD/MM/YYYY or can retrieve System Date automatically
• getCardPAN() : this functions asks either to generate a Luhn valid card PAN or enter manually
  • Uses GenerateLuhn() which essentially applies the Luhn algorithm to generate the card PAN
• readAccountDB() : this load the accounts database from the database file (read database section)
• saveTransaction() : saves APPROVED transactions with all details into the transactions database (read database section)

Instructions

• You would find demonstrated test cases in the "Submission Files/User Stories" Folder.
• This demonstrates how someone would use the Simulator.
• The test cases describe different scenarios that would happen:
  • EXCEED_MAX_AMOUNT : means that the user tried to make a transaction with more than specified max amount for card
  • DECLINED_STOLEN_CARD & INVALID_ACCOUNT : the card number is not present in the account database for the bank
  • DECLINED_INSUFFECIENT_FUND : transaction amount is greater than account balance
  • APPROVED : the transaction was successful and saved to transactions database

Databases

• AccountsDB.txt : has all accounts PAN (Primary Account Number) and accounts balance
• TransactionsDB.txt : this stores different data about the transaction (shown in the picture below)