Why Interface-like behavior in C++? - Purpose & Use Cases

The Big Idea

What if you could control many different devices with just one simple set of commands?

The Scenario

Imagine you have several different types of devices, like a printer, scanner, and fax machine, each with their own way of working. You want to write code that can use any of these devices without knowing the details of how each one works.

The Problem

Without a common way to interact with these devices, you would have to write separate code for each device type. This means repeating similar code many times, which is slow to write and easy to get wrong. If you add a new device, you must change lots of code everywhere.

The Solution

Using interface-like behavior, you define a common set of functions that all devices must have. Then, your code can work with any device through this common interface, without caring about the details. This makes your code cleaner, easier to maintain, and ready for new devices.

Before vs After

✗ Before

class Printer { void print(); };
class Scanner { void scan(); };
// Need separate code to handle each device

✓ After

struct IDevice { virtual void operate() = 0; virtual ~IDevice() = default; };
class Printer : public IDevice { void print(); void operate() override { print(); } };
class Scanner : public IDevice { void scan(); void operate() override { scan(); } };

What It Enables

You can write flexible programs that work with many different types of objects through a shared interface, making your code easier to extend and maintain.

Real Life Example

Think of a remote control that works with any TV brand because all TVs follow the same basic commands. Similarly, interface-like behavior lets your program control different objects in a uniform way.

Key Takeaways

Manual handling of different types leads to repeated and error-prone code.

Interface-like behavior defines a common set of functions for different types.

This approach makes code flexible, reusable, and easier to maintain.