What does the keyword “virtual” declare for a method or property? 

1 Answer

Answer :

The method or property can be overridden.

Related questions

Description : What does the keyword “virtual” declare for a method or property? 

Last Answer : The method or property can be overridden. 

Description : Methods must declare a return type, what is the keyword used when nothing is returned from the method?

Last Answer : void 

Description : What does the keyword virtual mean in the method definition? 

Last Answer : The method can be over-ridden. 

Description : Why is the virtual keyword used in code?

Last Answer : The Virtual keyword is used in code to define methods and the properties that can be overridden in derived classes.

Description : Can you declare an override method to be static if the original method is not static? 

Last Answer : No. The signature of the virtual method must remain the same. (Note: Only the keyword virtual is changed to keyword override)

Description : Can you declare an override method to be static if the original method is not static? 

Last Answer : No. The signature of the virtual method must remain the same. (Note: Only the keyword virtual is changed to keyword override)

Description : Can you declare the override method static while the original method is nonstatic?

Last Answer : No, you can’t, the signature of the virtual method must remain the same, only the keyword virtual is changed to keyword override. 

Description : Can we declare a method as sealed?

Last Answer : In C# a method can’t be declared as sealed. However, when we override a method in a derived class, we can declare the overridden method as sealed. By declaring it as sealed, we can avoid further overriding of this method.

Description : Write code to use threading and the lock keyword. 

Last Answer : using System; using System.Threading; namespace ConsoleApplication4 { class Class1 { [STAThread] static void Main(string[] args) { ThreadClass tc1 = new ThreadClass(1); ThreadClass tc2 = new ThreadClass( ... Console.WriteLine(threadNumber + " working"); Thread.Sleep(1000); } } } } }

Description : What is the volatile keyword used for?

Last Answer : It indicates a field can be modified by an external entity (thread, OS, etc.). 

Description : What keyword would you use for scope name clashes?

Last Answer : this

Description : Class methods to should be marked with what keyword?

Last Answer : static

Description : Define what is the use of the abstract keyword?

Last Answer : The modifier abstract is a keyword used with a class, to indicate that this class cannot itself have direct instances or objects, and it is intended to be only a ‘base’ class to other classes.

Description : Define what is the difference between string keyword and System. String class?

Last Answer : String keyword is an alias for System. String class. Therefore, the System. String and string keyword are the same, and you can use whichever naming convention you prefer. The String class provides many methods for safely creating, manipulating, and comparing strings.

Description : Explain the “static” keyword in C#?

Last Answer : “Static” keyword can be used for declaring a static member. If the class is made static then all the members of the class are also made static. If the variable is made static then it will have a single instance and the value change is updated in this instance.

Description : Why use the keyword “const” in C#? Give an example.

Last Answer : “Const” keyword is used for making an entity constant. We can’t reassign the value to constant. Eg: const string _name = “Test”;

Description : Define what is the difference between an abstract method & virtual method?

Last Answer : An Abstract method does not provide an implementation and forces overriding to the deriving class (unless the deriving class also an abstract class), whereas the virtual method has an ... abstract method does not provide implementation & forces the derived class to override the method.

Description : Can we override the private virtual method in C#?

Last Answer : No. We can’t override private virtual methods as it is not accessible outside the class.

Description : What si the difference between interface and abstractclass Select Answer:  1. interface contain only methods  2. we can't declare a variable for interface  3. interface contain only events  4. None  5. All

Last Answer : Ans : 2 The only Difference between Interface and Abstract class is we can declare a variable in abstract class but we can't declare in variable interface

Description : When do you absolutely have to declare a class as abstract?

Last Answer : 1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden. 2. When at least one of the methods in the class is abstract.

Description : Write some code to declare and use properties.

Last Answer : // instance public string InstancePr { get { return a; } set { a = value; } } //read-only static public static int ClassPr { get { return b; } }

Description : How do you declare a constant? 

Last Answer : public const int c1 = 5; 

Description : When do you absolutely have to declare a class as abstract?

Last Answer : 1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden. 2. When at least one of the methods in the class is abstract.

Description : When do you absolutely have to declare a class as abstract (as opposed to free-willed educated choice or decision based on UML diagram)?

Last Answer : When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.

Description : Can we declare a block as static in c#?

Last Answer : No, because c# does not support static block, but it supports static method.

Description : What’s the implicit name of the parameter that gets passed into the set method/property of a class?

Last Answer : Value. The data type of the value parameter is defined by whatever data type the property is declared as.

Description : What’s the implicit name of the parameter that gets passed into the set method/property of a class?

Last Answer : Value. The data type of the value parameter is defined by whatever data type the property is declared as.

Description : In C++, the keyword void was used ……….. A) To specify the return type of function when it is not returning any value. B) To indicate an empty argument list to a function. C) To declare the generic pointers. D) All of the above.

Last Answer : D) All of the above.

Description : Can abstract methods override virtual methods? 

Last Answer : Yes

Description : Write some code using interfaces, virtual methods, and an abstract class.

Last Answer : using System; public interface Iexample1 { int MyMethod1(); } public interface Iexample2 { int MyMethod2(); } public abstract class ABSExample : Iexample1, Iexample2 { public ABSExample( ... override void VIRTMethod2() { System.Console.WriteLine("VIRTMethod2 has been overridden"); } }

Description : Can you override private virtual methods? 

Last Answer : No, moreover, you cannot access private methods in inherited classes, have to be protected in the base class to allow any sort of access. 

Description : Can you override private virtual methods?

Last Answer : No. Private methods are not accessible outside the class.

Description : Can you override private virtual methods?

Last Answer : No, private methods are not accessible outside the class.

Description : What are the three possible settings for the CommandType property of a SqlCommand object or an OleDbCommand object, and what does each mean?

Last Answer : A Command object can have a CommandType property setting of Text, StoredProcedure, or TableDirect. When set to Text, the command executes the SQL string that is stored in the Command object's ... that the command should return the entire contents of the table indicated by the CommandText property. 

Description : Can a property be a ref or out parameter?

Last Answer : A property is not classified as a variable – it can’t be ref or out parameter. 

Description : What happens if you make a property static?

Last Answer : They become class properties. 

Description : Which of the following is used to make an Abstract class ? (A) Making atleast one member function as pure virtual function (B) Making atleast one member function as virtual function (C) Declaring as Abstract class using virtual keyword (D) Declaring as Abstract class using static keyword

Last Answer : (A) Making atleast one member function as pure virtual function

Description : Explain how to use the Begin and End methods on a Web Service to make an asynchronous method call.

Last Answer : Every public Web method on a Web Service can be called either synchronously or asynchronously. To make an asynchronous call to a Web method, you call the method named Begin, where is the name of ... returned by Begin. This will allow you to retrieve the actual data returned by the Web method.

Description : What is method overloading, and when is it useful?

Last Answer : Method overloading allows you to create several methods with the same name but different signatures. Overloading is useful when you want to provide the same or similar functionality to different sets of parameters.

Description : What does the Dispose method do with the connection object? 

Last Answer : Deletes it from the memory. To Do: answer better. The current answer is not entirely correct.

Description : What does assert() method do?

Last Answer : In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true. 

Description : What are the different ways a method can be overloaded?

Last Answer : Different parameter data types, different number of parameters, different order of parameters.

Description : How is method overriding different from method overloading? 

Last Answer : When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.

Description : What happens if you inherit multiple interfaces and they have conflicting method names?

Last Answer : It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay. To Do: Investigate 

Description : Can you allow a class to be inherited, but prevent the method from being over-ridden?

Last Answer : Yes. Just leave the class public and make the method sealed. 

Description : Are value types are slower to pass as method parameters? 

Last Answer : Yes

Description : What is an overloaded method?

Last Answer : An overloaded method has multiple signatures that are different. 

Description : Write code to show how a method can accept a varying number of parameters.

Last Answer : using System; namespace Console1 { class Class1 { static void Main(string[] args) { ParamsMethod(1,"example"); ParamsMethod(1,2,3,4); Console.ReadLine(); } static void ... o in list) { Console.WriteLine(o.ToString()); } } } }

Description : What does the Dispose method do with the connection object? 

Last Answer : Deletes it from the memory. To Do: answer better. The current answer is not entirely correct.

Description : What does assert() method do? 

Last Answer : In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true.