C Sharp Interview Prep: Questions

David Smith

1. What is the underlying type for enumerations?

2.What is the base class for the anonymous type?

3. Base upon the code below, how do you populate the even numbers integer array with even numbers? Use linq (Foreach or FindAll)

int [] numbers = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20};

4. What base class would you use to convey information for an event?

5. How often do a static constructor for a class execute?

6. What is the difference between const and readonly keywords

7. When dealing with exceptions, when is the finally block hit?

8. You use Action delegate when you?

9. What code do you write to declare a property with a set accessor inaccessible to code outside the current type, while keeping the get accessor accessible?

21 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sujeet Suman11y ago
Accepted answer
01. By default it is int.

02. Object

03. Take one integer array.
For each element of array "numbers" check it is divided by 2 or not.
If divided by 2 then add to your new array.

04. Object

05. It is called automatically before the first instance is created.

06. const: runtime constant
readonly: compile time constant

07. After try block: If error not occur.
After catch block: If error occur.

08. When we need no return type & pass a argument.

09. public int ID{ get; private set; }
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vipin kv11y ago
1. The default underlying type is (int) , we can change it to desired type, example
   enum ContractSize : uint
   {
      EURUSD = 125000,
      CADUSD = 100000
   }

2.Anonymous types are always generated as classes that have a base class of Object
3.int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
   var result = numbers.Where(x => x % 2 == 0);
   foreach (int val in result)
   {
      Console.Write(val+"\t");
   }

4.EventArgs is the base class for classes that contain event data, and provides a value to use for events that do not include event data.

5.Static constructor will execute only once either on creating first instance of class or accessing static member of class.
6.
Constants:
   a. Constants can be assigned values only at the time of declaration
   b. Constant variables have to be accessed using "Classname.VariableName"
c. Constants are known at compile time
Read Only:
   a. Read only variables can be assigned values either at runtime or at the time of instance    initialization via constructor
   b. Read only variables have to be accessed using the "InstanceName.VariableName"
   c. Read only variables are known at run time.

7.If there is no exception finally will execute sfter try block:and if there is any exception finally will execute after catch finally will execute even if there is throw statment in catch block

8.This Action<> generic delegate, points to a method that takes up to 16 Parameters and returns void. This delegate is used by collection to perform an action on each element of the collection.

9. public type PropertyName{get; private set;} example: public string Name{get;private set;}
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Sujeet Suman11y ago
3. Base upon the code below, how do you populate the even numbers integer array with even numbers? Use linq (Foreach or FindAll)

int [] numbers = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20};

This is my solution. What you think?

int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
int[] evenNumbers = Array.FindAll(numbers, i => i % 2 == 0);

Answer: You are absolutely right as per my understanding.
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Sujeet Suman11y ago
5. How often do a static constructor for a class execute?

The options are:

1. Only when the class inherits IDisposable
2. Everytime a new instance is created
3. Everytime the garbage collector remove all instances of the class
4. Exactly once in a given application domain
5. Up to Twice: once before the first instance is created, and once before any static member is accessed.

Answer: 4. Exactly once in a given application domain
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Sujeet Suman11y ago
What statement do you use to access the name property via the indexers of the customers collection?

1.cutomers.[1].Name
2.cutomers.Item{1}.Name
3.cutomers.Item(1).Name
4.cutomers(1).Name
5.cutomers[1].Name

Answer: 5.cutomers[1].Name
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Sujeet Suman11y ago
How do you use the postfix increment operator on a variable named i to increment the variable?

1.i++;
2.++i;
3.i=i+1;
4.i=i++;
5.i=++i;

Answer: 1. i++;
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David Smith11y ago
How do you use the postfix increment operator on a variable named i to increment the variable?

1.i++;
2.++i;
3.i=i+1;
4.i=i++;
5.i=++i;

Which option?
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David Smith11y ago
What statement do you use to access the name property via the indexers of the customers collection?

1.cutomers.[1].Name
2.cutomers.Item{1}.Name
3.cutomers.Item(1).Name
4.cutomers(1).Name
5.cutomers[1].Name

Which Option
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David Smith11y ago
3. Base upon the code below, how do you populate the even numbers integer array with even numbers? Use linq (Foreach or FindAll)

int [] numbers = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20};

This is my solution. What you think?

int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
int[] evenNumbers = Array.FindAll(numbers, i => i % 2 == 0);
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David Smith11y ago
5. How often do a static constructor for a class execute?

The options are:

1. Only when the class inherits IDisposable
2. Everytime a new instance is created
3. Everytime the garbage collector remove all instances of the class
4. Exactly once in a given application domain
5. Up to Twice: once before the first instance is created, and once before any static member is accessed.

Which option?
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David Smith11y ago
What will be the logic with the FindAll
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Sujeet Suman11y ago
3. You can use FindAll.
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Sujeet Suman11y ago
David if you feel our conversation is useful, then please accept my Answer.
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Sujeet Suman11y ago
7. When dealing with exceptions, when is the finally block hit?

The options are:

1. Whenever the catch block throws an exception
2. Only when a catch block is finish
3. Only when there are no errors at the end of a try block
4. Only at the end of a catch block
5. When the try block was fully or partially executed
Answer: 5. When the try block was fully or partially executed
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Sujeet Suman11y ago
08. You use Action delegate when you?.

The options are

1. Need to return a value
2. Need to pass parameters
3. Do not need to return a value
4. Need an operation to be thread safe
5. Do not need to pass a parameter

Answer: 3. Do not need to return a value
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David Smith11y ago
For all you can only choose one answer below. Which would you choose for this one below. I also added more choices for other questions. Review above.

If multiple answers are there, then
3. Do not need to return a value
4. Need an operation to be thread safe
5. Do not need to pass a parameter

Otherwise
4. Need an operation to be thread safe

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David Smith11y ago
7. When dealing with exceptions, when is the finally block hit?

The options are:

1. Whenever the catch block throws an exception
2. Only when a catch block is finish
3. Only when there are no errors at the end of a try block
4. Only at the end of a catch block
5. When the try block was fully or partially executed

Which one
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Sujeet Suman11y ago
System.EventArgs
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David Smith11y ago
08. When we need no return type & no argument.

The options are

1. Need to return a value
2. Need to pass parameters
3. Do not need to return a value
4. Need an operation to be thread safe
5. Do not need to pass a parameter

Which one
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David Smith11y ago
4. What base class would you use to convey information for an event?
The options are

1.System.Events.EventArg
2.System.Events.EventArgs
3.System.Events.EventsArgs
4.System.Events.EventArgs
5.System.Events.EventArg

Which one?
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David Smith11y ago
For question 3, could you provide logic you either and Foreach or FindAll linq statement?
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