Definition: An imperative language uses a sequence of statements to determine how to reach a certain goal. These statements are said to change the state of the program as each one is executed in turn. Examples: Java is an imperative language. For example, a program can be created to add a series of numbers: Each statement changes … Read more
A “Driver class” is often just the class that contains a main. In a real project, you may often have numerous “Driver classes” for testing and whatnot, or you can build a main into any of your objects and select the runnable class through your IDE, or by simply specifying “java classname.”
61 extends should go before implements:
A metaclass is the class of a class. A class defines how an instance of the class (i.e. an object) behaves while a metaclass defines how a class behaves. A class is an instance of a metaclass. While in Python you can use arbitrary callables for metaclasses (like Jerub shows), the better approach is to make it … Read more
What is the precise difference between encapsulation and abstraction?
C++ is usually considered a “multi-paradigm” language. That is, you can use it for object-oriented, procedural, and even functional programming. Those who would deny that C++ is OO generally have beef with the fact that the primitive types are not objects themselves. By this standard, Java would also not be considered OO. It is certainly … Read more
In your method setDetails you haven’t specified anything for the return type, if it is not returning anything then specify void For Voter class for Candidates class One other thing, (Thanks to Frank Pavageau) your class name is Candidates and you have defined the constructor with Candidate without s, that is why it is being considered as a normal method, and thus should have a return type. You your rename … Read more
On a Java OOP project I got three errors on my constructor: .\Voter.java:14: error: invalid method declaration; return type required .\Candidates.java:7: error: invalid method declaration; return type required .\Candidates.java:14: error: invalid method declaration; return type required codes for constructor: i declared my constructors like this: Anything I missed?
If you think about the Greek roots of the term, it should become obvious. Poly = many: polygon = many-sided, polystyrene = many styrenes (a), polyglot = many languages, and so on. Morph = change or form: morphology = study of biological form, Morpheus = the Greek god of dreams able to take any form. So … Read more
As mentioned by other here: Interfaces are not necessary in Python. This is because Python has proper multiple inheritance, and also ducktyping, which means that the places where you must have interfaces in Java, you don’t have to have them in Python. That said, there are still several uses for interfaces. Some of them are covered by … Read more