Answer 1

Hello, Elias !
Let's explain the strategy pattern the easy way:

You have a class Car() with a method run(), so you use it this way in a pseudo language:

mycar = new Car() mycar.run()

Now, you may want to change the run()behavior on the fly, while the program is executing. For example, you might want to simulate a motor failure or the use of a "boost" button in a video game.

There are several ways to do this simulation: using conditional statements and a flag variable is one way. The strategy pattern is another: it delegates the behavior of the run() method to a subclass:

Class Car() {
this.motor = new Motor(this);
//passing "this" is important for the motor so it knows what it is running method run() {
this.motor.run()
}
method changeMotor(motor) {
this.motor = motor }
}
If you want to change the car's behavior, you can just change the motor. 
https://stackoverflow.com/questions/91932/how-does-the-strategy-pattern-work