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Bank Account with Encapsulation + Validation
Scenario: You are building a bank account module for a console-based finance app. What to implement: - Create a BankAccount class with private fields and safe public methods. - Validate deposits/withdrawals and block invalid operations. - Parse complex input lines (spaces, quotes, special chars) to drive the flow. ✅ Student task: - Implement only the TODO methods: 1) BankAccount.Deposit(...) 2) BankAccount.Withdraw(...) 3) InputParser.ParseAmount(...) - Main() should remain unchanged. Ask yourself: - What should happen when input contains currency symbols, commas, and spaces?
✅ Input examples above include: spaces, quotes, ₹ symbol, commas, emoji, unicode (α/β), and special chars like @ # % !.
Replace with your own test data if needed.
Boilerplate C# console program (students implement ONLY TODO methods)
Ctrl+C
using System; // Console, Exception
namespace ItTechGenie.M1.OOP.Q1
{
public class Program
{
public static void Main()
{
Console.WriteLine("Paste input lines, end with EMPTY line:"); // ask user for input
var lines = ConsoleInput.ReadLines(); // read multi-line input
var engine = new BankEngine(); // orchestrates operations
engine.Run(lines); // execute commands
}
}
public static class ConsoleInput
{
public static string[] ReadLines()
{
// Read until empty line for easy testing.
var list = new System.Collections.Generic.List<string>(); // store lines
while (true)
{
var line = Console.ReadLine(); // read one line
if (string.IsNullOrWhiteSpace(line)) break; // stop on empty
list.Add(line); // add line
}
return list.ToArray(); // return array
}
}
public class BankEngine
{
private readonly System.Collections.Generic.Dictionary<int, BankAccount> _accounts = new(); // store accounts
public void Run(string[] lines)
{
foreach (var raw in lines) // process each line
{
var cmd = Command.Parse(raw); // parse command structure
if (cmd.Name == "ACC_CREATE") // create account
{
int id = int.Parse(cmd.Get("id")); // parse id
string name = cmd.Get("name"); // get name
decimal opening = InputParser.ParseAmount(cmd.Get("opening")); // parse amount with symbols
_accounts[id] = new BankAccount(id, name, opening); // create and store
}
else if (cmd.Name == "ACC_DEPOSIT") // deposit
{
int id = int.Parse(cmd.Get("id")); // id
decimal amt = InputParser.ParseAmount(cmd.Get("amount")); // amount
_accounts[id].Deposit(amt, cmd.Get("note")); // ✅ calls TODO
}
else if (cmd.Name == "ACC_WITHDRAW") // withdraw
{
int id = int.Parse(cmd.Get("id")); // id
decimal amt = InputParser.ParseAmount(cmd.Get("amount")); // amount
_accounts[id].Withdraw(amt, cmd.Get("note")); // ✅ calls TODO
}
else if (cmd.Name == "PRINT") // print summary
{
int id = int.Parse(cmd.Get("id")); // id
Console.WriteLine(_accounts[id].GetSummary()); // output
}
}
}
}
public class BankAccount
{
private decimal _balance; // encapsulated balance
public int Id { get; } // read-only id
public string HolderName { get; } // read-only name
public BankAccount(int id, string holderName, decimal opening)
{
Id = id; // assign
HolderName = holderName; // assign
_balance = opening; // set opening balance
}
// ✅ TODO: Student must implement only this method
public void Deposit(decimal amount, string note)
{
// TODO:
// - validate amount > 0
// - update _balance
// - print receipt line with note (note can contain spaces/special chars)
throw new NotImplementedException();
}
// ✅ TODO: Student must implement only this method
public void Withdraw(decimal amount, string note)
{
// TODO:
// - validate amount > 0
// - validate amount <= _balance
// - update _balance
// - print receipt line with note
throw new NotImplementedException();
}
public string GetSummary()
{
return $"Account[{Id}] {HolderName} | Balance={_balance}"; // summary string
}
}
public static class InputParser
{
// ✅ TODO: Student must implement only this method
public static decimal ParseAmount(string raw)
{
// TODO:
// - handle currency symbols (₹, $, etc.)
// - handle commas: "10,500.75"
// - handle spaces: "₹ 1,999.25"
// - return decimal value
throw new NotImplementedException();
}
}
public class Command
{
public string Name { get; } // command name
private readonly System.Collections.Generic.Dictionary<string, string> _kv; // parameters
private Command(string name, System.Collections.Generic.Dictionary<string, string> kv)
{
Name = name; // assign
_kv = kv; // assign
}
public string Get(string key) => _kv.TryGetValue(key, out var v) ? v : ""; // safe get
public static Command Parse(string line)
{
// Very small parser: COMMAND|k=v|k="v with spaces"
var parts = line.Split('|'); // split parts
var name = parts[0].Trim(); // command name
var kv = new System.Collections.Generic.Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
for (int i = 1; i < parts.Length; i++) // read key-value tokens
{
var p = parts[i]; // token
var idx = p.IndexOf('='); // locate '='
if (idx <= 0) continue; // skip invalid
var key = p.Substring(0, idx).Trim(); // key
var val = p.Substring(idx + 1).Trim(); // value
val = val.Trim().Trim('"'); // remove quotes
kv[key] = val; // store
}
return new Command(name, kv); // build
}
}
}