C# Questions & Answers on Collection Classes for Fresher

1. Which among the following is not the ordered collection class?

a) BitArray
b) Queue
c) Stack
d) None of the mentioned

Answer: a

2. Which among the following is not an interface declared in System.Collection namespace?

a) IDictionaryComparer
b) IEnumerable
c) IEnumerator
d) Icomparer

Answer: a

3. Which among the following is the correct way to find out the number of elements currently present in an ArrayListCollection called arr?

a) arr.Capacity
b) arr.Count
c) arr.MaxIndex
d) arr.UpperBound

Answer: b

4. Which statement is correct about the C#.NET code snippet given below?

1. Stack st = new Stack();

2. st.Push("Csharp");

3. st.Push(7.3);

4. st.Push(8);

5. st.Push('b');

6. st.Push(true);

a) Unsimilar elements like “Csharp”,7.3,8 cannot be stored in the same stack collection.
b) Boolean values can never be stored in Stack collection
c) Perfectly workable code
d) All of the mentioned

Answer: c

5. Which is the correct statement about an ArrayList collection that implements the IEnumerable interface?

a) To access members of ArrayList from the inner class, it is necessary to pass ArrayList class’s reference to it
b) The inner class of ArrayList can access ArrayList class’s members
c) The ArrayList class consist of inner class that implements the IEnumerator interface
d) All of the mentioned

Answer: d

6. Which among the following is the correct way to access all the elements of the Stack collection created using the C#.NET code snippet given below?

1. Stack st = new Stack();

2. st.Push(10);

3. st.Push(20);

4. st.Push(-5);

5. st.Push(30);

6. st.Push(6);

a) IEnumerable e;
e = st.GetEnumerator();
while (e.MoveNext())
Console.WriteLine(e.Current);
b) IEnumerator e;
e = st.GetEnumerator();
while(e.MoveNext())
Console.WriteLine(e.Current);
c) IEnumerable e;
e = st.GetEnumerable();
while(e.MoveNext())
Console.WriteLine(e.Current);
d) None of the mentioned

Answer: b

7. The correct code to access all the elements of the queue collection created using the C#.NET code snippets given below is?

1. Queue q = new Queue();

2. q.Enqueue("Harsh");

3. q.Enqueue('a');

4. q.Enqueue(false);

5. q.Enqueue(70);

6. q.Enqueue(8.5);

a) IEnumerator e;
e = q.GetEnumerator();
while(e.MoveNext())
Console.WriteLine(e.Current);
b) IEnumerable e;
e = q.GetEnumerator();
while(e.MoveNext())
c) IEnumerable e
e = q.GetEnumerable();
while(e.MoveNext())
Console.WriteLine(e.Current);
d) All of the mentioned

Answer: a

8. Which statements among the following are correct about the Collection Classes available in Framework Class Library?

a) Elements of a collection cannot be transmitted over a network
b) Elements stored in a collection can be modified only if all the elements are of similar types
c) Elements stored in a Collection can be retrieved but cannot be modified
d) Collection classes make use of efficient algorithms to manage the collection,hence improving performance of the program

Answer: d

9. Among the given collections which one is I/O index based?

a) ArrayList
b) List
c) Stack
d) Queue

Answer: a

10. Which among the given statements are correct about the Stack collection?

a) It can be used for evaluation of expressions
b) It is used to maintain a FIFO list
c) Top most element of the Stack collection can be accessed using the Peek()
d) All of the mentioned

Answer: d

11. A HashTable t maintains a collection of names of states and capital city of each state.Which among the following finds out whether “New delhi” state is present in the collection or not?

a) t.HasValue(“New delhi”);
b) t.ContainsKey(“New delhi”);
c) t.HasKey(“New delhi”);
d) t.ContainsValue(“New delhi”);

Answer: b

12. In which of the following collections is the I/O based on a key?

a) BitArray
b) SortedList
c) Queue
d) Stack

Answer: b

13. The wrong statements about a HashTable collection are?

a) It is a keyed collection
b) It is a ordered collection
c) It’s not an indexed collection
d) It implements a IDictionaryEnumerator interface in its inner class

Answer: b