update exercise 3 code and instructions

Author: ChrisHowd

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Solution/BankAccount.cs

@@ -35,6 +35,12 @@ public BankAccount(BankAccount existingAccount)
         this.AccountType = existingAccount.AccountType;
     }
 
+    // Method to deposit money into the account. Only accessible within the assembly
+    internal void SetBalance(double amount)
+    {
+        Balance = amount;
+    }
+
     // Method to display account information
     public string DisplayAccountInfo()
     {

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Solution/BankCustomer.cs

@@ -7,7 +7,7 @@ public partial class BankCustomer
     private static int s_nextCustomerId;
     private string _firstName = "Tim";
     private string _lastName = "Shao";
-    public readonly string customerId;
+    public readonly string CustomerId;
 
     static BankCustomer()
     {
@@ -19,13 +19,13 @@ public BankCustomer(string firstName, string lastName)
     {
         FirstName = firstName;
         LastName = lastName;
-        this.customerId = (s_nextCustomerId++).ToString("D10");
+        this.CustomerId = (s_nextCustomerId++).ToString("D10");
     }
 
     // Copy constructor with unique customerId
     public BankCustomer(BankCustomer existingCustomer)
     {
-        this.customerId = (s_nextCustomerId++).ToString("D10");
+        this.CustomerId = (s_nextCustomerId++).ToString("D10");
         this.FirstName = existingCustomer.FirstName;
         this.LastName = existingCustomer.LastName;
     }

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Solution/BankCustomerMethods.cs

@@ -20,22 +20,6 @@ public void UpdateName(string firstName, string lastName)
     // Method to display customer information
     public string DisplayCustomerInfo()
     {
-        return $"Customer ID: {customerId}, Name: {FullName()}";
-    }
-
-    // Override Equals method to compare customers by customerId
-    public override bool Equals(object obj)
-    {
-        if (obj == null || GetType() != obj.GetType())
-            return false;
-
-        BankCustomer other = (BankCustomer)obj;
-        return customerId == other.customerId;
-    }
-
-    // Override GetHashCode method
-    public override int GetHashCode()
-    {
-        return customerId.GetHashCode();
+        return $"Customer ID: {CustomerId}, Name: {FullName()}";
     }
 }

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Solution/Extensions.cs

@@ -7,7 +7,7 @@ public static class BankCustomerExtensions
     // Extension method to check if the customer ID is valid
     public static bool IsValidCustomerId(this BankCustomer customer)
     {
-        return customer.customerId.Length == 10;
+        return customer.CustomerId.Length == 10;
     }
 
     // Extension method to greet the customer

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Solution/Transactions.cs

@@ -9,7 +9,7 @@ public static void Deposit(BankAccount account, double amount)
     {
         if (amount > 0)
         {
-            account.Balance += amount;
+            account.SetBalance(account.Balance + amount);
         }
     }
 
@@ -18,7 +18,7 @@ public static bool Withdraw(BankAccount account, double amount)
     {
         if (amount > 0 && account.Balance >= amount)
         {
-            account.Balance -= amount;
+            account.SetBalance(account.Balance - amount);
             return true;
         }
         return false;
@@ -38,6 +38,6 @@ public static bool Transfer(BankAccount sourceAccount, BankAccount targetAccount
     // Method to apply interest to the account balance
     public static void ApplyInterest(BankAccount account)
     {
-        account.Balance += account.Balance * BankAccount.interestRate;
+        account.SetBalance(account.Balance + account.Balance * BankAccount.InterestRate);
     }
 }

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Starter/BankCustomer.cs

@@ -7,7 +7,7 @@ public class BankCustomer
     private static int s_nextCustomerId;
     private string _firstName = "Tim";
     private string _lastName = "Shao";
-    public readonly string customerId;
+    public readonly string CustomerId;
 
     static BankCustomer()
     {
@@ -19,7 +19,7 @@ public BankCustomer(string firstName, string lastName)
     {
         FirstName = firstName;
         LastName = lastName;
-        this.customerId = (s_nextCustomerId++).ToString("D10");
+        this.CustomerId = (s_nextCustomerId++).ToString("D10");
     }
 
     public string FirstName
@@ -50,7 +50,7 @@ public void UpdateName(string firstName, string lastName)
     // Method to display customer information
     public string DisplayCustomerInfo()
     {
-        return $"Customer ID: {customerId}, Name: {ReturnFullName()}";
+        return $"Customer ID: {CustomerId}, Name: {ReturnFullName()}";
     }
 
 }

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Starter/Extensions.cs

@@ -7,7 +7,7 @@ public static class BankCustomerExtensions
     // Extension method to check if the customer ID is valid
     public static bool IsValidCustomerId(this BankCustomer customer)
     {
-        return customer.customerId.Length == 10;
+        return customer.CustomerId.Length == 10;
     }
 
     // Extension method to greet the customer

DownloadableCodeProjects/LP1_classes-properties-methods/Classes_M3/Starter/Program.cs

@@ -24,9 +24,9 @@
 BankAccount account2 = new BankAccount(customer2.CustomerId, 1500, "Checking");
 BankAccount account3 = new BankAccount(customer3.CustomerId, 2500, "Checking");
 
-Console.WriteLine($"Account 1: Account # {account1.AccountNumber}, type {account1.AccountType}, balance {account1.Balance}, rate {BankAccount.interestRate}, customer ID {account1.CustomerId}");
-Console.WriteLine($"Account 2: Account # {account2.AccountNumber}, type {account2.AccountType}, balance {account2.Balance}, rate {BankAccount.interestRate}, customer ID {account2.CustomerId}");
-Console.WriteLine($"Account 3: Account # {account3.AccountNumber}, type {account3.AccountType}, balance {account3.Balance}, rate {BankAccount.interestRate}, customer ID {account3.CustomerId}");
+Console.WriteLine($"Account 1: Account # {account1.AccountNumber}, type {account1.AccountType}, balance {account1.Balance}, rate {BankAccount.InterestRate}, customer ID {account1.CustomerId}");
+Console.WriteLine($"Account 2: Account # {account2.AccountNumber}, type {account2.AccountType}, balance {account2.Balance}, rate {BankAccount.InterestRate}, customer ID {account2.CustomerId}");
+Console.WriteLine($"Account 3: Account # {account3.AccountNumber}, type {account3.AccountType}, balance {account3.Balance}, rate {BankAccount.InterestRate}, customer ID {account3.CustomerId}");
 
 // Step 3: Demonstrate the use of BankCustomer properties
 Console.WriteLine("\nUpdating BankCustomer 1's name...");

Instructions/Labs/l2p2-lp1-m3-exercise-implement-classes-csharp-apps.md

@@ -465,7 +465,37 @@ Use the following steps to complete this section of the exercise:
 
     Notice that the `Deposit` method now accepts a `BankAccount` parameter named `account`, and that it uses the `account` object to access the `Balance` property. The `account.Balance` property is updated using `amount` parameter.
 
-1. Repeat this method update process to correct the issues in the remaining `Transactions` class methods.
+1. Notice that `account.Balance` can't be modified from the static method because the setter is private.
+
+    To update the `Balance` property, you need to add an `internal` method to the `BankAccount` class that enabled classes within the assembly to modify the `Balance` property. This keeps the `Balance` property encapsulated within the `BankAccount` class while allowing the `Transactions` class to update the `Balance` property.
+
+1. Add the following `SetBalance` method to the `BankAccount` class:
+
+    ```csharp
+
+    internal void SetBalance(double balance)
+    {
+        Balance = balance;
+    }
+
+    ```
+
+1. To use the `SetBalance` method in the `Transactions` class, update the `Deposit` method using the following code:
+
+    ```csharp
+
+    // Method to deposit money into the account
+    public static void Deposit(BankAccount account, double amount)
+    {
+        if (amount > 0)
+        {
+            account.SetBalance(account.Balance + amount);
+        }
+    }
+
+    ```
+
+1. Repeat the process used to update `Deposit` to correct the issues in the remaining `Transactions` class methods.
 
     Ensure that each of the Transaction methods accepts a `BankAccount` parameter and uses the `BankAccount` instance to access the required properties and fields.