ATM Simulator

• Terminal based front end
• File systems are used for the backend data persistence

2 main users - ADMIN and USER

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The file names are the account ID of the user
The User file contains

• Password
• Account ID
• Name of the account holder
• Balance amount

The Admin file contains

• Password
• 100Rs count
• 500Rs count
• 2000Rs count

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• The file values are stored in global attributes for access throughout the program
• Admin file is read by default to read the note(2000, 500, 100) counts and store them in global variables - As they will help maintain the money present in the ATM
• The function choices are driven by a integer switch case which redirects to specific functions based choice values

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USER

The main functionalities displayed by the user are :

• View account details
  • The global parameters read from the user file are displayed
• Withdraw Money
  • Ensure that the money requested to withdraw is less than the account balance and the amount present in the atm machine
  • Money withdrawn can be paid in the denominations of 100,500,2000 only. Hence enter appropriate withdrawal amount
  • Deduct the amount requested from the account balance and the atm machine.
  • Display message of success
• Deposit Money
  • Number of notes of different denominations prompted to enter
  • Ensures number of notes entered >= 0
  • Update the global note count attributes
  • Update the balance of the account
  • Success message displayed
• Change password/pin
  • Validate the current password/PIN
  • Prompt entry of new PIN on successfull validation of old PIN
  • Success message displayed
• Quit

A valid Account ID needs to be provided to access the account functionalities On providing the account ID, the respective account file is read if present - password is obtained on the read and verified to ensure legetimate access. Password pin is of size 4 The user is given 2 chances to enter the valid ID/valid PIN in case of entering an INVALID ID/PIN, after which the program terminates.

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ADMIN

The main functionalities displayed by the Admin are :

• View denomination count
  • The global parameters of the note counts are displayed
• Deposit notes
  • Number of notes of different denominations prompted to enter
  • Ensures number of notes entered >= 0
  • Update the global note count attributes
  • Success message displayed
• Quit

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• After all the operations executed, before exiting, all the global attributes are written back to the opened files
• Message is sent to the user conveying all changes made have been persisted to the files
• All open files are closed

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Executing the ATM Simulator

1. Clone/Download the source code along with the admin and user account files
   • Can create more account files if required following the same format as given in the example files
   • Ensure all the files are in the same location
2. compile the .c file using gcc
3. Run the executable generated