LINQ (Language-Integrated Query) in C Sharp MCQ question and answer with solution | C# Program MCQs

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();
        }
    }

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");
    }
}

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();
    }
}

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();
}

expr is type

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

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();
    }
}