Classes ​

A class groups data (fields) with the functions that use it (methods). private fields can only be used inside the class. Create an object by calling the class:

class Temperature {
    private celsius: Float;

    constructor(celsius: Float) {
        this.celsius = celsius;
    }

    fn fahrenheit(): Float {
        return this.celsius * 9.0 / 5.0 + 32.0;
    }
}

print(Temperature(20.0).fahrenheit());   // 68

A class can extend another and reuse its methods, and implements an interface that lists the methods it must have.

Your turn ​

Give Stack a pop() method that removes and returns the last item, and a size() method.