Problem definition

An Automated Teller Machine (ATM) is a self-service terminal that enables bank customers to perform financial transactions without interacting with a human teller or visiting a physical bank branch. Through ATMs, users can perform essential banking operations such as depositing cash, withdrawing money, checking account balances, and transferring funds between accounts. ATMs are typically placed in accessible public locations like banks, malls, airports, and convenience stores to provide round-the-clock banking services.

In this LLD interview case study, your focus will be on:

• Enabling secure card-based access and PIN verification for users.

• Supporting core transactions: cash withdrawal, deposit, balance inquiry, and fund transfer.

• Managing cash inventory within the ATM, including withdrawal limits and handling ...