LINQ (Language
practice.

Choose the namespace in which the interface IEnumerable is declared?

Select the Keyword which supports the run time type identification?

What will be the output of the following C# code snippet?

static void Main() 
{
    int[] nums = { 1, 2, 3, 4, 5 };
    Console.Write("Original order: ");
    foreach(int i in nums)
    Console.Write(i + " ");
    Array.Reverse(nums);
    Console.Write("Reversed order: ");
    foreach(int i in nums)
    Console.Write(i + " ");
    Console.WriteLine();
}

Choose the wrong statement about the LINQ?

What will be the output of the following C# code snippet?

class Program
{
    static void Main(string[] args)
    {
        int[] nums = { 1, -2, 3, 0, -4, 5};
        var posNums = from n in nums
                      where n >= 0
                      select n;
       foreach (int i in posNums) 
       Console.Write(i + " ");
       Console.WriteLine();
       Console.ReadLine();
   }
}

Select the interfaces implemented by array class.

What will be the output of the following C# code snippet?

class Program
{
    static void Main(string[] args)
    {
        int[] nums = { 1, -2, 3, 0, -4, 5 };
        var posNums = from n in nums
                       where n > -5 && n < 6
                       orderby n descending
                       select n;
        Console.Write("The positive values in nums: ");
        foreach (int i in posNums) Console.Write(i + " ");
        Console.WriteLine();
        Console.ReadLine();
    }
}

Select the class which is the base class for all arrays in C#?

What will be the output of the following C# code snippet?

class Program
{
    static void Main(string[] args)
    {
        int[] nums = { 1, -2, 3, 0, -4, 5 };
        var posNums = from n in nums
                      where n % 2 ==0
                      select n;
           Console.Write("The positive values in nums: ");
           foreach (int i in posNums) Console.Write(i + " ");
           Console.WriteLine();
           Console.ReadLine();
       }
}

What will be the output of the following C# code snippet?

class Program
{
    static void Main(string[] args)
    {
        int[] nums = { 16,  9, 25};
        var posNums = from n in nums
                      where n > 0 
                      select Math.Sqrt(n);
 
        Console.Write("The positive values in nums: ");
        foreach (int i in posNums) Console.Write(i + " ");
        Console.WriteLine();
        Console.ReadLine();
    }
}

Select the namespace which should be included while making use of LINQ operations?

What will be the output of the following C# code snippet?

class Program
    {
        static void Main(string[] args)
        {
 
            int[] nums = { 1, -2, -3, 5 };
            var posNums = from n in nums
                          orderby n descending
                          select n*4 / 2;
            Console.Write("The values in nums: ");
            foreach (int i in posNums) Console.Write(i + " ");
            Console.WriteLine();
            Console.ReadLine();
        }
    }

What will be the output of the following C# code snippet?

class A {}
class B : A {}
class CheckCast 
{
    static void Main() 
    {
        A a = new A();
        B b = new B();
        b = a as B;
        b = null;
        if(b==null)
        Console.WriteLine("The cast in b = (B) a is NOT allowed.");
        else
        Console.WriteLine("The cast in b = (B) a is allowed");
    }
}

Select the statement which are correct about RTTI(Runtime type identification)?

In the following C# code, what does the output represent?

class Program
{
    static void Main(string[] args)
    {
        int[] nums = { 1, -2, 3, 0, -4, 5 };
        var posNums = from n in nums
                      where n > 0
                      select n;
        int len = posNums.Count();
        Console.WriteLine(len);
        Console.ReadLine();
    }
}

What will be the output of the following C# code snippet?

static void Main(string[] args)
{
    string[] strings = {"beta", "alpha", "gamma"};
    Console.WriteLine("Array elements: ");
    DisplayArray(strings);
    Array.Reverse(strings); 
    Console.WriteLine("Array elements now: ");
    DisplayArray(strings);
    Console.ReadLine();
 }
 public static void DisplayArray(Array array)
 {
     foreach (object o in array)
     {
         Console.Write("{0} ", o);
     }
         Console.WriteLine();
}

What does the following C# code signify?

expr is type

Which operator among the following is used to perform the operation of boxing, unboxing, reference and identity conversions?

What does the following property define in C#?

public static int BinarySearch<T>(T[] array, int index, int length, T value)

What will be the output of the following C# code snippet?

class Program
{
    static void Main(string[] args)
    {
        Expression<Func<int, int, bool>>
        IsFactorExp = (n, d) => (d != 0) ? (n % d) == 0 : false;
        Func<int, int, bool> IsFactor = IsFactorExp.Compile();
        if (IsFactor(10, 5))
        Console.WriteLine("5 is a factor of 10.");
        if (!IsFactor(343, 7))
        Console.WriteLine("7 is not a factor of 10.");
        Console.ReadLine();
    }
}