1. Type A type is a collection of values. For example, integers can be considered a type that include these values { ... , -2, -1, 0, 1, 2, 3, ... } 2. Data item A data item is one of the values included in a type. For example, taking the example of above of the integer type consisting of { ... , -2, -1, 0, 1, 2, 3, ... }, we can say that the number 2 is a data item of the integer type. 3. Data type A data type is a type together with all the operations that can be done to the values of the type. For example, with the integer type, we can add values of the integer together, we can multiply them etc .. 4. Abstract data type
An Abstract data type (ADT), is a way to talk about a data type in the context of a programing language. An ADT will describe a data type together with all the operations that should be performed on the task. However, the ADT does not tell us how we should implement those operations. For instance, an ADT my describe a data type that holds integers and to which we can add values, retrieve values, remove value. So the ADT just tells us what we should be able to do, but it doesn't tell us how we should do it. 5. Data structure Following from the above discussion of the ADT which just told us what we should be able to do with our data type, a data structure is the implementation of the ADT. With a data structure we have decided on a way to implement the requirements that were presented in the ADT. For example, we might decide that the way that we will access a value in the data type is by traversing each value in the data type. Or that the way we can remove a value from the data type is only by removing the last value. 6. Class
In some languages like java, when we implement an ADT and therefore create a data structure, the ADT and the data structure that we implemented from it are together referred to as a Class. In java, for example we have the Array class, the Integer Class the Char Class and more. 7. Member function The operations that our ADT can do will be implemented in the data structure and Class by a member function also known as a method. So in languages like java, we have seen in previous courses that each Classes like arrays or Integers have properties and methods attached to them. Those methods are what are referred to as member functions. 8. Data members A class can contain properties and methods. Those properties are also known as data members. Reference Shaffer, C. (2011). A Practical Introduction to Data Structures and Algorithm Analysis. Blacksburg: Virginia. Tech