Make all tests pass

csharp-fundamentals-strings.Main/Core.cs

@@ -14,7 +14,7 @@ public class Core
         //TODO: 1. The brokenUrl member above contains an invalid URL. There's a z instead of an s in the protocol (httpz instead of https).
         // Using the `replace` method on brokenUrl, set the fixedUrl member below to the correct value.
         // https://learn.microsoft.com/en-us/dotnet/api/system.string.replace?view=net-7.0
-        public string fixedUrl => string.Empty;
+        public string fixedUrl => brokenUrl.Replace('z', 's');
 
 
         // Here's a documentation link for all string methods, use it to figure out how to complete the rest of these requirements:
@@ -23,27 +23,27 @@ public class Core
 
         //TODO: 2. There are currently some upper case characters in the URL. Using an appropriate string method on the fixedUrl member above,
         // set the value of lowerCasedUrl.
-        public string lowerCasedUrl => string.Empty;
+        public string lowerCasedUrl => fixedUrl.ToLower();
 
 
         //TODO: 3. There is still white space on both ends of the URL! Use the appropriate string method to trim that white space
         // and set the value of the url member below
-        public string url => string.Empty;
+        public string url => lowerCasedUrl.Trim();
 
 
         //TODO: 4. Using the appropriate string method on url, set the value of the protocol member below
-        public string protocol => string.Empty;
+        public string protocol => url[..5];
 
 
         //TODO: 5. Using the appropriate string method on url, set the value of the domain member below
-        public string domain => string.Empty;
+        public string domain => url[8..(8+13)];
 
 
         //TODO: 6. Set the length member below to the length of the url member
-        public int length => 0;
+        public int length => url.Length;
 
 
         //TODO: 7. Using concatenation and existing members, set the faqUrl member below to the faq page of the boolean website
-        public string faqUrl => string.Empty;
+        public string faqUrl => $"{protocol}://{domain}/faq";
     }
 }

csharp-fundamentals-strings.Main/Extension.cs

@@ -42,7 +42,7 @@ public StringBuilder one()
 
             // 1. Using the sb variable above, add "Hello, world!" to the StringBuilder
             // WRITE YOUR CODE BETWEEN THIS LINE...
-
+            sb.Append("Hello, world!");
 
 
             // ...AND THIS LINE
@@ -58,7 +58,11 @@ public StringBuilder two()
             // 2. After adding the message, use an appropriate StringBuilder method to reverse it
             // WRITE YOUR CODE BETWEEN THIS LINE...
 
-
+            // Found no specific reverse method for StringBuilder, so used an array instead.
+            sb.Append("Hello, world!");
+            char[] charArray = sb.ToString().ToCharArray();
+            Array.Reverse(charArray);
+            sb.Clear().Append(charArray);
 
             // ...AND THIS LINE
 
@@ -72,7 +76,8 @@ public StringBuilder three()
             // 1. Using the sb variable above, add "Hello, world!" to the StringBuilder
             // 2. After adding the message, remove the comma.
             // WRITE YOUR CODE BETWEEN THIS LINE...
-
+            sb.Append("Hello, world!");
+            sb.Replace(",", "");
 
 
             // ...AND THIS LINE
@@ -87,7 +92,8 @@ public StringBuilder four()
             // 1. Using the sb variable above, add "Hello, world!" to the StringBuilder
             // 2. After adding the message, replace the word "world" with the word "C#"
             // WRITE YOUR CODE BETWEEN THIS LINE...
-
+            sb.Append("Hello, world!");
+            sb.Replace("world", "C#");
 
 
             // ...AND THIS LINE

csharp-fundamentals-strings.Main/Program.cs

@@ -1,2 +1,6 @@
 // See https://aka.ms/new-console-template for more information
+using csharp_fundamentals_strings.Main;
+
 Console.WriteLine("Hello, World!");
+Extension ex = new Extension();
+ex.two();