Interview Questions → CSHARP 2.0 → C# 2.0 Questionnaire IV

C# 2.0 Questionnaire IV

How to get windows logged-in user name in C#?

System.Security.Principal.WindowsIdentity.GetCurrent().Name

How to get computer name in C#?

Environment.MachineName

How to delete last 4 elements in the list in C#?

Consider an example

List<int> lst = new List<int>() { 1, 2, 3, 4, 5, 6, 7 };
lst.RemoveRange(3, 4);

Here 3 is the starting point and 4 is the count. So this method will delete elements 4, 5, 6 and 7.

What are jagged array?

A Jagged array is an array of arrays. For example

int[][] array = new int[2][];
array[0] = new int[] { 1, 2, 3 };
array[1] = new int[] { 4, 5, 6 };
 
for (int i = 0; i < array.Length; i++)
{
    for (int j = 0; j < array[i].Length; j++)
    {
       Console.WriteLine(array[i][j]);
    }
}

Can I make the constructor of an abstract class as private?

No. Consider the following example

public abstract class MyAbstractClass
{                                                                                                                   
    private MyAbstractClass()
    {
 
    }
    public abstract void Display();
 
}
 
public class DerivedClass : MyAbstractClass
{
    public DerivedClass()
    {
 
    }
    public override void Display()
    {
        throw new NotImplementedException();
    }
}

This code will give an error MyAbstractClass()' is inaccessible due to its level. If you make the constructor of the abstract class as private, then object of derived class cannot be created, as it first calls the constructor of base class, which is private

What is an arraylist?

Arraylist is the collection of items where each item can be treated as an object. It means you can store items of different data type in the same arraylist.

You can declare arraylist as

//C#
ArrayList list = new ArrayList();
‘vb.net
Dim list as new ArrayList()

Posted By -

Karan Gupta

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