Design Pattern

Strategy Design Pattern

Strategy is a behavioural design pattern that lets you define a family of algorithms, put each of them into a separate class, and make their objects interchangeable.

This was introduced super quickly in CS247. Isn’t this just implementing basic Polymorphism?

• Yup, though there are other ways to implement strategy pattern… StackOverflow

When to use Strategy Pattern?

We want one class to use an algorithm that may be changed at runtime.

Resources

• https://refactoring.guru/design-patterns/strategy

Example

If you need something more advanced, where the the weapon also needs to know what kind of hero you are hitting, look into Visitor Pattern.

class Hero {
	Weapon* w;
	public:
		Hero(Weapon* w): w{w} {}
		void strike() {
			cout << "strike with weapon " << w->getName() << endl;
		}
};
 
class Weapon {
	public:
		virtual string getName() = 0;
}
 
class Sword: public Weapon {
	public:
		virtual string getName() override {
			return "sword";
		}
}
 
class Bow: public Weapon {
	public:
		virtual string getName() override {
			return "bow";
		}
}
 
class Wand: public Weapon {
	public:
		virtual string getName() override {
			return "wand";
		}
}
 
Sword* s;
Hero h{s};
h.strike();