Can you explain the concept of design patterns and their role in designing software systems?

Design patterns are proven solutions to common software design problems. They serve as templates that help create flexible, extendable, and maintainable systems.

Role of patterns:

• Improve code quality through reuse of tested solutions.
• Facilitate communication among developers, as patterns have common names and descriptions.
• Help avoid common mistakes and anti-patterns.
• Accelerate development by providing ready-made architecture schemes.

Example: The Singleton pattern ensures that a class has only one instance and provides a global access point to it.

public class Singleton {
    private static Singleton instance;
    private Singleton() { }
    public static Singleton Instance {
        get {
            if (instance == null) {
                instance = new Singleton();
            }
            return instance;
        }
    }
}

Here, Singleton is a pattern that guarantees a single instance of a class and provides a global point of access.