abstract class - Pure virtual methods in C#? -

i've been told make class abstract:

public abstract class airplane_abstract 

and make method called move virtual

 public virtual void move()         {             //use property ensure there valid position object             double radians = planeposition.direction * (math.pi / 180.0);              // change x location x vector of speed             planeposition.x_coordinate += (int)(planeposition.speed * math.cos(radians));              // change y location y vector of speed             planeposition.y_coordinate += (int)(planeposition.speed * math.sin(radians));         } 

and 4 other methods should "pure virtual methods." exactly?

they right now:

public virtual void turnright() {     // turn right relative airplane     if (planeposition.direction >= 0 && planeposition.direction < position.max_compass_direction)         planeposition.direction += 1;     else         planeposition.direction = position.min_compass_direction;  //due north } 

my guess whoever told write "pure virtual" method c++ programmer rather c# programmer... equivalent abstract method:

public abstract void turnright(); 

that forces concrete subclasses override turnright real implementation.