Abstraction

concept oop Abstraction is the process of hiding complex implementation details and showing only the essential features of an object. It reduces complexity and allows the user to interact with a simplified Interface.

• Example: When you press the “Brake” pedal, you don’t need to know if the car uses Hydraulic pads or Regenerative braking. You just know “Car Stops”.

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Mechanisms of Abstraction

1. Abstract Classes (Partial Abstraction) A class that cannot be instantiated on its own and may contain a mix of implemented methods and abstract (empty) methods.

• Use Case: Sharing common code among related classes (e.g., Animal has sleep() logic, but makeSound() is abstract).

2. Interfaces (Total Abstraction) A contract that specifies what a class must do, but not how. It contains only method signatures (and sometimes constants).

• Use Case: Defining a capability (e.g., Drawable, Serializable) that unrelated classes can share.

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Language Comparison

C++ (Pure Virtual)

No interface keyword. Uses classes with pure virtual functions (= 0).

class Drawable {
public:
    virtual void draw() = 0; // Pure Virtual
};

Java

Distinct keywords for abstract class and interface.

interface Drawable {
    void draw(); // Implicitly public abstract
}

Rust (Traits)

Traits are the sole mechanism for abstraction.

trait Drawable {
    fn draw(&self);
    
    // Default Implementation (Optional)
    fn description(&self) {
        println!("I am drawable");
    }
}

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