Free 70-483: MCSD Programming in C Exam Questions and Answers

You are developing a C# application that sums selected values. The application contains the following code: 01 int total = 0; 02 for (int i = 1; i <= 6; i++) 03 { 04 if (i % 2 == 0) continue; 05 if (i == 5) break; 06 total += i; 07 } For each of the following statements, select Yes if the statement is true. Otherwise, select No. Statement 1: After the loop exits, total equals 4. Statement 2: Line 05 is evaluated when i equals 2. Statement 3: Line 06 executes three times.

Answer each statement, then reveal.

1. After the loop exits, total equals 4.YesNo
2. Line 05 is evaluated when i equals 2.YesNo
3. Line 06 executes three times.YesNo

You are developing a C# application that processes an array named items by using the following code: 01 int processed = 0; 02 Parallel.For(0, items.Length, i => 03 { 04 Process(items[i]); 05 // insert code here 06 }); After the loop completes, processed must equal items.Length. You need to update the counter in a thread-safe manner with the least overhead. Which code segment should you insert at line 05?

• AA. Volatile.Write(ref processed, processed + 1);
• BB. processed++;
• CC. lock (new object()) { processed++; }
• DD. Interlocked.Increment(ref processed);

You are developing a C# application that builds a comma-separated list of names. The result variable must contain Ana,Ben,Cy with no trailing comma. 01 var names = new List<string> { "Ana", "Ben", "Cy" }; 02 var sb = new StringBuilder(); 03 foreach (var n in names) 04 { 05 [Target 1] 06 } 07 string result = [Target 2]; Code segments: A. sb.Append(n).Append(','); B. sb.AppendLine(n); C. sb.ToString().TrimEnd(',') D. sb.ToString().TrimStart(',') E. sb.ToString().Replace(",", "") F. sb.Insert(0, n); Which code segment should you use for each target? Each code segment may be used once, more than once, or not at all.

Drag or tap each item onto its target, then reveal.

You are developing a C# application that contains a method named LogState. Calls to LogState must be compiled only when the DEBUG compilation symbol is defined. The call sites must not be modified. Which attribute should you apply to the LogState method?

• AA. [Obsolete("DEBUG")]
• BB. [DebuggerHidden]
• CC. [Conditional("DEBUG")]
• DD. [DebuggerStepThrough]

You are developing a C# application that contains the following classes: 01 class Shape { public virtual string Describe() { return "Shape"; } } 02 class Circle : Shape { public override string Describe() { return "Circle"; } } 03 class Ring : Circle { public new string Describe() { return "Ring"; } } The application runs the following code: 04 Shape s = new Ring(); 05 Circle c = new Ring(); 06 Ring r = new Ring(); 07 Console.WriteLine(s.Describe() + c.Describe() + r.Describe()); What is the output?

• AA. CircleRingRing
• BB. CircleCircleRing
• CC. RingRingRing
• DD. ShapeCircleRing

You are developing a WPF application. When a user clicks a button, the UI freezes and does not recover. The application contains the following code: 01 private void LoadButton_Click(object sender, RoutedEventArgs e) 02 { 03 string data = GetDataAsync().Result; 04 resultText.Text = data; 05 } 06 private async Task<string> GetDataAsync() 07 { 08 var client = new HttpClient(); 09 string s = await client.GetStringAsync(url); 10 return s.ToUpper(); 11 } The UI thread must remain responsive while the download runs. You need to resolve the problem. What should you do?

• AA. Change line 09 to use await client.GetStringAsync(url).ConfigureAwait(false).
• BB. Change line 03 to use Task.Run(() => GetDataAsync()).Result.
• CC. Change line 06 to remove the async keyword and return client.GetStringAsync(url) directly.
• DD. Change line 01 to declare the handler as async void and change line 03 to use await GetDataAsync().

You are developing a C# method named DownloadAllAsync that is declared with the async modifier. The method contains the following code: 01 Task<byte[]>[] tasks = urls.Select(u => client.GetByteArrayAsync(u)).ToArray(); 02 // insert code here 03 byte[][] files = tasks.Select(t => t.Result).ToArray(); The method must continue only after every download has completed, and it must not block the calling thread while waiting. Which code segment should you insert at line 02?

• AA. await Task.WhenAny(tasks);
• BB. await tasks[0];
• CC. await Task.WhenAll(tasks);
• DD. Task.WaitAll(tasks);

You are developing a generic class named Repository<T>. The class must create instances of T by calling a parameterless constructor and then call the Save method defined in the IEntity interface on each instance. You need to declare the class so that the code compiles. Which declaration should you use?

• AA. class Repository<T> where T : IEntity
• BB. class Repository<T> where T : IEntity, new()
• CC. class Repository<T> where T : new(), IEntity
• DD. class Repository<T> where T : class, IEntity

You are developing a class named OrderQueue. The class exposes the following event: 01 public event EventHandler<OrderEventArgs> OrderReceived; Subscribers can unsubscribe from the event on other threads at any time. You need to raise the event so that a NullReferenceException is never thrown when no subscriber is attached, even if the last subscriber unsubscribes while the event is being raised. Which code segment should you use?

• AA. var handler = OrderReceived; handler(this, new OrderEventArgs(id));
• BB. OrderReceived?.Invoke(this, new OrderEventArgs(id));
• CC. OrderReceived(this, new OrderEventArgs(id));
• DD. if (OrderReceived != null) OrderReceived(this, new OrderEventArgs(id));

You are debugging a console application. The application adds a TextWriterTraceListener that writes to a file named log.txt, and it records progress by calling Trace.WriteLine. When the application terminates because of an unhandled exception, the last several messages are missing from log.txt. You need to ensure that every message appears in the file even if the application crashes. What should you do? Each correct answer presents a complete solution. Choose two.

Select 2 answers.

• AA. Set the TextWriterTraceListener.TraceOutputOptions property to DateTime.
• BB. Add a ConsoleTraceListener to Trace.Listeners.
• CC. Set Trace.AutoFlush to true before the first message is written.
• DD. Call Trace.Flush after each call to Trace.WriteLine.