C# Multiple Choice Questions:

Attempting to invoke a derived-class-only method through a base-class variable is an error.

True

False

Which of the following property specify the duration of a Timer in System.Timers.Timer

Events

Interval

Duration

Enabled

The .NET languages have which of the following in common?

Syntax

Keywords

Base Class Library

Which of the following is an appropriate declaration of an abstract method?

public abstract int GetScore() { }

public abstract int GetScore();

public int GetScore() as abstract;

none of the above

What type of methods can be called without instantiating an object first?

static

dynamic

primary

Assume an extension method is defined as:

static class Util

{ public static int Negate(this int i)

{

return -i;

}

}

Which of the following is correct?

int x = 591; Console.WriteLine($"x.Negate {x.Negate()}");

int x = 591; Console.WriteLine($"x.Negate {Util.Negate(x)}");

both A and B

None of the above

To define an extension method for a type:

The extension method can be an instance method

The first parameter must be of the type being extended

The first parameter must be proceeded by this keyword

Both A, B and C

Both B and C

Both A and C

var addresses = new[] {

new { CompanyName = "Alpine Ski House", City = "Berne", Country = "Switzerland"},

new { CompanyName = "Coho Winery", City = "San Francisco", Country = "United States"},

new { CompanyName = "Wingtip Toys", City = "London", Country = "United Kingdom"},

new { CompanyName = "Wide World Importers", City = "Tetbury", Country = "United Kingdom"}

};

var usCompanies =

addresses.Where(addr => String.Equals(addr.Country, "United States"))

.Select(usComp => usComp.CompanyName)

What type is variable usCompanies?

int

string

IEnumerable

anonymous type

Assume Horse class is defined as:

class Horse : ILandBound, IJourney

{

int ILandBound.NumberOfLegs() { return 4; }

int IJourney.NumberOfLegs() { return 3; }

}

Which of the following is correct if:

Horse horse = new Horse(); int legs = horse.NumberOfLegs();

legs variable has a value of 4

legs variable has a value of 3

Code will not compile

None of the choices are correct

Which method can you use to find the minimum value in a sequence?

(from i in myArray select i).Min()

from Min(i) in myArray select i

from i in myArray select Min(i)

from i in Min(myArray) select i