![]() ![]() For example, both Java and Python have a type called int that is used to store integers. Recall that most programming languages store data using a few primitive data types. Before we can do that, we should spend a little time talking about data types and how that relates to inheritance. In this course, we’re going to dive a bit deeper into how it works and some of the theory behind it. This is a topic that comes up many times, and you may have already learned about it in the past. In this chapter, we’re going to cover inheritance and polymorphism in object-oriented programming languages. Subsections of Types Data Types YouTube Video Resources If we want to create a new student, we would create an instance of the class Student which is an object of type Student:Īnd the type of a changes from an integer (at the first assignment) to string (at the second assignment).Ĭ#, Java, C, C++, and Kotlin are all statically typed languages, while Python, JavaScript, and Ruby are dynamically typed languages. Hours: the number of credit hours in the course """Records a final grade for a course taken by this student. ![]() _credit_hoursĭef add_course_grade(self, grade: Grade, hours: int) -> None: """Gets the student's grade point average. _credit_hours: int = 0 # properties for first and last omitted def gpa(self) -> float: For example, we could define an enumerator called Grade:ĭef _init_(self, first: str, last: str) -> None: In addition to built-in types, most programming languages support user-defined types, that is, new types defined by the programmer. In either case, our computer is able to use the data type assigned to each variable to determine how it should be treated and what operations it can perform. Python, however, will raise a TypeError since it doesn’t know what the plus operator means when applied to a string and an integer. In Java, the plus operator can also be used for concatenation, so the result will be 5 apples. What should happen in that case? As it turns out, each language does this a bit differently. In the second case, one operand x is an integer, but the other operand string is a string value. So, the computer will know that the plus operator should be treated like addition, and it will add those two integer values together. In the first case, the two operands x and y are both integers. X: int = 5 y: int = 7 string: str = " apples" print(x + y) # 12 print(x + string) # TypeErrorĬonsider the last two lines of each example - we are using the plus + operator between two different variables. You’ve already used types extensively in your programming up to this point. It also defines how the value can be treated and what operations can be performed on it. In computer science, a type is a way of categorizing a variable by its storage strategy, i.e., how it is represented in the computer’s memory. ![]() Some key terms to learn in this chapter are:īefore we can discuss polymorphism in detail, we must first understand the concept of types. In this chapter we’ll look at how polymorphism is commonly implemented in object-oriented languages. While encapsulation of state and behavior into objects is the most central theoretical idea of object-oriented languages, polymorphism - specifically in the form of inheritance - is a close second. Some form of polymorphism can be found in nearly all programming languages. a function or class name) to represent multiple types. In computer science, it refers to the ability of a single symbol (i.e. That content is licensed under a Creative Commons BY-NC-SA Much of the content in this chapter was adapted from Nathan Bean’s CIS 400Ĭourse at K-State, with the author’s permission. ![]()
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