Mida tähendab täht 'L' objektorienteeritud programmeerimise SOLID põhimõtetes?

The letter "L" in the SOLID principles represents the Liskov Substitution Principle (LSP).

This principle states that objects of a subclass should be replaceable with objects of the superclass without affecting the correctness of the program. In other words, if class B inherits from class A, then objects of class B should behave in such a way that they can be used in place of objects of class A without unexpected errors or changes in behavior.

Example of violating LSP:

class Bird {
    func fly() {}
}

class Ostrich: Bird {
    override func fly() {
        fatalError("Ostrich cannot fly")
    }
}

Here, Ostrich inherits from Bird but cannot correctly implement the fly method, which violates LSP.

Proper class design helps adhere to this principle, improving code reliability and extensibility.