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c sharp Online Quiz - 1

Description: c sharp Online Quiz - 1
Number of Questions: 7
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Tags: c sharp
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A variable which is declared inside a method is called a________variable

  1. Serial

  2. Local

  3. Private

  4. Static


Correct Option: B

AI Explanation

To answer this question, you need to understand the concept of variable scope in programming.

Option A) Serial - This option is incorrect because "serial" is not a term used to describe a variable declared inside a method.

Option B) Local - This option is correct because a variable declared inside a method is called a local variable. Local variables are only accessible within the method in which they are declared.

Option C) Private - This option is incorrect because "private" is a term used to describe the visibility of class members, not variables declared inside a method.

Option D) Static - This option is incorrect because "static" is a term used to describe variables that belong to the class itself, rather than instances of the class.

The correct answer is B) Local. This option is correct because a variable declared inside a method is indeed called a local variable.

Feature of a local variable

  1. It can be used anywhere in the program

  2. It must accept a class

  3. It must be declared within a method

  4. It represent a class object


Correct Option: D

AI Explanation

To answer this question, we need to understand the concept of a local variable in programming.

A local variable is a variable that is declared and used within a specific block of code, typically within a method or function. It is only accessible within the scope of that block of code and cannot be accessed from outside.

Let's go through each option to understand why it is correct or incorrect:

Option A) It can be used anywhere in the program - This option is incorrect because a local variable is limited to the scope in which it is declared. It cannot be used outside of that specific block of code.

Option B) It must accept a class - This option is incorrect because a local variable does not necessarily have to accept a class. It can store any data type, including primitive data types like integers or booleans.

Option C) It must be declared within a method - This option is correct. A local variable must be declared within a method or function. It is typically declared at the beginning of the method and is only accessible within that method.

Option D) It represents a class object - This option is incorrect. A local variable does not necessarily represent a class object. It can represent any data type, not just class objects.

The correct answer is Option C. A local variable must be declared within a method.

  1. Freeing memory on the stack.

  2. Avoiding memory leaks.

  3. Freeing memory occupied by unreferenced objects.

  4. Closing unclosed database collections.

  5. Closing unclosed files.


Correct Option: A,D,E
  1. It is allocated at compile time

  2. Declaration and initialization is separated

  3. It is allocated at runtime

  4. all of these


Correct Option: C
  1. System.Int8

  2. System.Int16

  3. System.Int32

  4. System.Int64


Correct Option: C

Which of the following method of the command object is best suited when you have aggregate functions in a SELECT statement?

  1. ExecuteScalar

  2. ExecuteReader

  3. ExecuteNonQuery

  4. None of the above


Correct Option: A

AI Explanation

To answer this question, we need to understand the different methods of the command object in ADO.NET and determine which one is best suited when working with aggregate functions in a SELECT statement.

Option A) ExecuteScalar - This method is used when you want to retrieve a single value from the database, such as the result of an aggregate function. It executes the query and returns the first column of the first row in the result set. This option is correct because it allows you to retrieve the result of the aggregate function directly.

Option B) ExecuteReader - This method is used to execute a query that returns a result set, and it is typically used when you want to read multiple rows of data. While it can be used to retrieve the result of an aggregate function, it would require additional code to extract the value from the result set. Therefore, it is not the best option when you have aggregate functions in a SELECT statement.

Option C) ExecuteNonQuery - This method is used for executing SQL statements that do not return a result set, such as INSERT, UPDATE, or DELETE statements. It is not suitable for retrieving the result of an aggregate function.

Option D) None of the above - This option is incorrect because option A (ExecuteScalar) is the best method to use when you have aggregate functions in a SELECT statement.

Therefore, the correct answer is option A) ExecuteScalar. This option is correct because it is the best suited method when you have aggregate functions in a SELECT statement, as it allows you to directly retrieve the result of the aggregate function.

  1. RowChanged

  2. ColumnChanged

  3. RowChanging

  4. All of above


Correct Option: D
Explanation:

To solve this question, the user needs to have knowledge of the DataTable object and the events that it exposes.

The DataTable object is a part of the ADO.NET framework and represents a table of data in memory. It is used to store and manipulate data retrieved from a database or other data source.

Now, let's go through each option and explain why it is right or wrong:

A. RowChanged: This option is correct. The RowChanged event is exposed by the DataTable object. It is raised when a row in the DataTable has been changed.

B. ColumnChanged: This option is correct. The ColumnChanged event is exposed by the DataTable object. It is raised when a value in a column of the DataTable has been changed.

C. RowChanging: This option is correct. The RowChanging event is exposed by the DataTable object. It is raised before a row in the DataTable is about to be changed.

D. All of the above: This option is correct. All of the events mentioned in options A, B, and C are exposed by the DataTable object. These events provide different points in the data manipulation process where custom logic can be executed.

Therefore, the correct answer is:

The Answer is: D. All of the above

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