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Object Classes for a Bank Account

publish date: 1969/12/31 00:00:00 UTC

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Using the UML graphical notation for object classes, design a BankAccount object class. Which of the following sets of attributes and operations is most appropriate for a BankAccount class?

Attributes: branchCode, sortCode, swiftCode; Operations: openBranch(), closeBranch(), listAccounts()

Attributes: transactionId, timestamp, merchantName; Operations: authorize(), reverse(), void()

Attributes: accountNumber, holderName, balance, accountType; Operations: deposit(amount), withdraw(amount), getBalance(), transfer(amount, targetAccount), getStatement()

Attributes: username, password, sessionToken; Operations: login(), logout(), changePassword()

Correct Answer

Attributes: accountNumber, holderName, balance, accountType; Operations: deposit(amount), withdraw(amount), getBalance(), transfer(amount, targetAccount), getStatement()

Explanation

A BankAccount object class should encapsulate the account's own data (accountNumber, holderName, balance, accountType) and provide operations that act on that data (deposit, withdraw, getBalance, transfer, getStatement). The other options describe authentication objects, transaction records, or branch management objects - not bank accounts. The key OO principle is that attributes represent state and operations represent behaviours that change or query that state.

Reference

Software Engineering, Ian Sommerville, 10th edition

Quizzes you can take where this question appears

Design and Implementation: Exercises