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  • Question
  • Suppose on pushing a button an object is to be notified, but it is not known until runtime which object should be notified. Which of the following programming constructs should be used to implement this idea?


  • Options
  • A. Attribute
  • B. Delegate
  • C. Namespace
  • D. Interface
  • E. Encapsulation

  • Correct Answer
  • Delegate 


  • Delegates problems


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    • 1. Which of the following statements are correct about delegates?

      1. Delegates are not type-safe.
      2. Delegate is a user-defined type.
      3. Only one method can be bound with one delegate object.
      4. Delegates can be used to implement callback notification.
      5. Delegates permit execution of a method on a secondary thread in an asynchronous manner.

    • Options
    • A. 1 and 2 only
    • B. 1, 2 and 3 only
    • C. 2, 4 and 5 only
    • D. 4 and 5 only
    • E. All of the above
    • Discuss
    • 2. Which of the following is the correct way to call the function MyFun() of the Sample class given below?

      class Sample
      {
          public int MyFun(int i)
          {
              Console.WriteLine("Welcome to CuriousTab.com !" );
              return 0;
          }
      }

    • Options
    • A.
      delegate void del(int i);
      Sample s = new Sample();
      deld = new del(ref s.MyFun);
      d(10);
    • B.
      delegate int del(int i);
      Sample s = new Sample(.);
      del = new delegate(ref MyFun);
      del(10);
    • C.
      Sample s = new Sample();
      delegate void del = new delegate(ref MyFun);
      del(10);
    • D.
      delegate int del(int i);
      del d;
      Sample s = new Sample();
      d = new del(ref s.MyFun);
      d(10);
    • Discuss
    • 3. Which of the following are the correct ways to declare a delegate for calling the function func() defined in the sample class given below?

      class Sample
      {
          public int func(int i, Single j)
          {
              /* Add code here. */
          }
      }

    • Options
    • A. delegate d(int i, Single j);
    • B. delegate void d(int, Single);
    • C. delegate int d(int i, Single j);
    • D. delegate void (int i, Single j);
    • E. delegate int sample.func(int i, Single j);
    • Discuss
    • 4. With which of the following can the ref keyword be used?

      1. Static data
      2. Instance data
      3. Static function/subroutine
      4. Instance function/subroutine

    • Options
    • A. 1, 2
    • B. 3, 4
    • C. 1, 3
    • D. 2, 4
    • E. All of the above
    • Discuss
    • 5. Which of the following statements are correct about a delegate?

      1. Inheritance is a prerequisite for using delegates.
      2. Delegates are type-safe.
      3. Delegates provide wrappers for function pointers.
      4. The declaration of a delegate must match the signature of the method that we intend to call using it.
      5. Functions called using delegates are always late-bound.

    • Options
    • A. 1 and 2 only
    • B. 1, 2 and 3 only
    • C. 2, 3 and 4 only
    • D. All of the above
    • E. None of the above
    • Discuss
    • 6. Which of the following statements are correct about delegates?

    • Options
    • A. Delegates cannot be used to call a static method of a class.
    • B. Delegates cannot be used to call procedures that receive variable number of arguments.
    • C. If signatures of two methods are same they can be called through the same delegate object.
    • D. Delegates cannot be used to call an instance function. Delegates cannot be used to call an instance subroutine.
    • Discuss
    • 7. Suppose a Generic class called SortObjects is to be made capable of sorting objects of any type (Integer, Single, Byte etc.). Which of the following programming constructs should be used to implement the comparision function?

    • Options
    • A. Namespace
    • B. Interface
    • C. Encapsulation
    • D. Delegate
    • E. Attribute
    • Discuss
    • 8. Which of the following statements is incorrect about a delegate?

    • Options
    • A. A single delegate can invoke more than one method.
    • B. Delegates can be shared.
    • C. Delegate is a value type.
    • D. Delegates are type-safe wrappers for function pointers.
    • E. The signature of a delegate must match the signature of the method that is to be called using it.
    • Discuss
    • 9. Which one of the following classes are present System.Collections.Generic namespace?

      1. Stack
      2. Tree
      3. SortedDictionary
      4. SortedArray

    • Options
    • A. 1 and 2 only
    • B. 2 and 4 only
    • C. 1 and 3 only
    • D. All of the above
    • E. None of the above
    • Discuss
    • 10. For the code snippet shown below, which of the following statements are valid?

      public class TestCuriousTab
      {
          public void TestSub<M> (M arg)
          {
              Console.Write(arg);
          }
      }
      class MyProgram
      {
          static void Main(string[] args)
          {
              TestCuriousTab tab = new TestCuriousTab();
              tab.TestSub("CuriousTab ");
              tab.TestSub(4.2f);
          }
      }

    • Options
    • A. Program will compile and on execution will print: CuriousTab 4.2
    • B. A non generic class Hello cannot have generic subroutine.
    • C. Compiler will generate an error.
    • D. Program will generate a run-time exception.
    • E. None of the above.
    • Discuss


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