Overview

Kotlin is an example of an ‘object-oriented programming’ language. You’ve used some objects before, but Kotlin forces you to really get into objects. Today, we’ll focus on the concepts core to “OOP”, which you’ll use heavily in Kotlin but apply across lots of other programming languages.

Basic Learning Objectives

Before class, you should be able to:

  • Describe at a high level how classes can “inherit” code from another class
  • Describe the difference between an interface and a class

Advanced Learning Objectives

After class, you should be able to:

  • Create a subclass
  • Implement an interface
  • Explain how instance variables work with inheritance

Readings

You should read the following:

Checks

You should submit answers to the following on the Gradescope assignment linked through Moodle. You may upload your answers in one file or different files and the name of the files doesn’t matter.

  1. Given the base class Person, complete the derived class Student below.

    Student should have the following properties:

    • classYear: Student’s anticipated graduation year
    • major1: Student’s first major.
    • major2: Student’s second major, if applicable.
    • minor: A list of a student’s minors (because apparently, there isn’t a limit to the number of minors at Carleton…)

    Student should have one member function declareMajor that:

    • sets major1 to the declared major if the student’s first major is “Undeclared”
    • sets major2 to the declared major if the student already has a first major but the student’s second major is “Undeclared”
    • prints “You have too many majors! Talk to your advisor.” if the student already two majors

  2. Given the interface RegistrarRecord, implement the member function printCourses for StudentRecord and ProfessorRecord.

    • Both StudentRecord and ProfessorRecord should have the same property courses, which is a list of courses.
    • However, printCourses for StudentRecord first prints “I’m currently taking these courses:”, followed by the list of courses, while printCourses for ProfessorRecord first prints “I’m currently teaching these courses:” followed by the list of courses instead.