C# Practice Exercises

Encapsulated Bank Account

This exercise applies encapsulation instead of exposing writable state.

How it works

Protect a balance with validated domain methods.

A private setter prevents arbitrary changes while Deposit enforces the account rule.

Runnable C# example

Program.cs

using System;
class BankAccount(decimal opening)
{
    public decimal Balance { get; private set; } = opening;
    public void Deposit(decimal amount)
    {
        if (amount <= 0) throw new ArgumentOutOfRangeException(nameof(amount));
        Balance += amount;
    }
}
class Program
{
    static void Main() { var account = new BankAccount(100); account.Deposit(50); Console.WriteLine(account.Balance); }
}

Expected output

Practice with the debugger

Set a breakpoint on an important assignment or condition, click Debug, and inspect the local values before stepping to the next line.