C# : Interview questions (56-60)

 

Questions :

• How do you implement a property with both get and set accessors?
• Explain the difference between a property and a field.
• What is the purpose of the "this" keyword in C#?
• How do you create an indexer in C#?
• What is the purpose of the "base" keyword in C#?

C# : Interview questions (51-55)

Answers :

1. Implementing a Property with Both Get and Set Accessors:

A property in C# can have both get and set accessors to encapsulate the access to a private field. The get accessor is used to return the property value, and the set accessor is used to assign a new value to the property.

public class Person
{
    private string name;

    public string Name
    {
        get { return name; }
        set { name = value; }
    }
}

In this example, the Name property encapsulates the private field name. The get accessor returns the value of name, and the set accessor assigns a new value to name.

2. Difference Between a Property and a Field:

• Field:
• A field is a variable declared directly in a class or struct.
• Fields can be public, private, protected, or internal.
• Fields are accessed directly.

public class Person
{
    public string name; // Field
}

• Property:
• A property provides a controlled way to access the private fields of a class.
• Properties can include logic in their accessors.
• Properties can be read-only, write-only, or read-write.
• Properties use get and set accessors.

public class Person
{
    private string name;

    public string Name
    {
        get { return name; }
        set { name = value; }
    }
}

3. Purpose of the "this" Keyword in C#:

The this keyword in C# refers to the current instance of the class. It is used to access members (fields, properties, methods) of the current instance, especially when there is a naming conflict between method parameters and class members.

public class Person
{
    private string name;

    public void SetName(string name)
    {
        this.name = name; // "this" refers to the current instance's "name" field
    }
}

In this example, the this keyword distinguishes the name field of the current instance from the name parameter of the SetName method.

4. Creating an Indexer in C#:

An indexer in C# allows an object to be indexed like an array. Indexers are defined using the this keyword followed by square brackets.

public class StringCollection
{
    private string[] collection = new string[10];

    public string this[int index]
    {
        get { return collection[index]; }
        set { collection[index] = value; }
    }
}

In this example, the StringCollection class has an indexer that allows access to the collection array using an index.

5. Purpose of the "base" Keyword in C#:

The base keyword in C# is used to access members of the base class from within a derived class. It can be used to call base class constructors, methods, or access fields and properties.

public class BaseClass
{
    public void Display()
    {
        Console.WriteLine("Base class method");
    }
}

public class DerivedClass : BaseClass
{
    public void Show()
    {
        base.Display(); // Call method from base class
        Console.WriteLine("Derived class method");
    }
}

In this example, the base keyword is used in the Show method of the DerivedClass to call the Display method from the BaseClass.

These explanations and examples should help you understand the implementation and use of these concepts in C#.

C# : Interview questions (61-65)