159.339 ATM

Task

Your task is to write a PHP program that simulates a very simple ATM (Automatic Teller Machine).

The input to your program will consist of two plain-text files: acct.txt and tranz.txt

acct.txt will contain current balances for a number of bank accounts in the following format:

< INT account ID> < FLOAT balance>

For example:

101 345.23
102 43.2
103 0
104 33

tranz.txt will contain a ledger of tranactions (Deposits/Withdrawals) that you will need to apply against the corresponding accounts. Each transaction will be on a separate line and will be in the following format:

< INT account ID> < CHAR transaction type> < FLOAT amount>

For example:

ID Type(D,W) Amount
105 D 200
108 W 500.55
101 D 45.12
102 D -555

Please note, the first line of this file is the header and should be ignored. Define and use a class called Account - write its definition in a file called Account.php.

Write a PHP program that reads account information from acct.txt and creates account objects. Then reads and applies transactions to them as specified by tranz.txt; name the main file for this program index.php.

Once processing is finished, store updated balances in update.txt in the same format as acct.txt.

If a transaction is invalid (invalid transaction type - anything other than D or W, invalid amount or the account does not have sufficient balance), then nothing is to be changed. Account class should raise a custom exception BadTranzException defined in BadTranzException.php that should be caught in index.php. On catching such an exception, you will create a new object of type BadTranz (which you will define in BadTranz.php). This object should contain information about the transaction (acc ID, type, amount) and the reason why it is a bad transaction.

At the end of the program, output the following information in a structured way, using HTML (to be viewed in a browser):

a) Total number of transactions (as recorded in tranz.txt)
b) Total number of valid transactions
c) A table containing each invalid transaction and the reason for it being invalid

Example output:

There were 28 transactions in total.
There were 21 valid transactions.
The following transactions are invalid:

Place all your code in a namespace based on your name and subnamespace A1, e.g. jdoe\A1.

All class files should be loaded by a PSR-4 compliant autoloader that you are to write. You can use the example provided as part of PSR-4 as a starting point:

github.com/php-fig/fig-standards/blob/master/accepted/PSR-4-autoloader-examples.md

Place all class files inside src/A1/ subdirectory. Project root should only contain autoloader.php and index.php (that will require the autoloader.php). You can place all the txt files into the project root as well.

Hint: Do not use '' or / for directory separators in paths defined in your autoloader. This will make your code incompatible with other operating systems. Use PHPs predefined constant DIRECTORY_SEPARATOR that will be equal to the appropriate directory separator for the operating system that is executing the code.