Question

Assume your sketch has a variable named silo, which stores an object that is defined by a class you have created. The name of the class is Cylinder. The Cylinder class has a method named volume, which calculates the volume of a cylinder using its property values and returns the calculated value. Which line of code is the correct line to use the silo variable, calculate volume, and store that value in a new variable.

a. let v = [silo volume];
b. let v = volume(silo);
c. let v = silo.volume();
d. let v = silo[volume];
e. let v = cylinder.volume(radius, height);

Answer 1

c. let v = silo.volume();

Step-by-step explanation:

When you create and initialize a new object you pass through that object's class constructor. The constructor is in charge of initializing all the necessary variables for that class including radius and height. Once you save the object in a specific variable (silo) you need to call the class methods through that variable, using the '.' command. Therefore, in this scenario, in order to call the volume() method you would need to call it from the silo object and save it to the v variable, using the following statement.

let v = silo.volume();