Abstract Data Types
- 1. Abstract Data Types (ADT) • Problem solving with a computer: processing data. • Need to define the data type and the operation to be performed on the data. • The definition of the data type and the definition of the operation to be applied to the data is part of the idea behind an abstract data type (ADT). • ADT is a collection of data together with a set of operations on that data. ADT = Data + Operations 1
- 2. Abstract Data Types (ADT) • The ADT specifies • What can be stored in the Abstract Data Type • What operations can be done on/by the Abstract Data Type. 2 The concept of abstraction means: 1. We know what a data type can do. 2. How it is done is hidden. Definition : Abstract Data type (ADT) is defined as a mathematical model with a collection of operations defined on that model.
- 3. Abstract Data Types (ADT) ADT Types • Simple ADTs • Predefined data types are Simple ADTs. • Examples: int, float, double, char, bool • Consider Integer ADT: • This type of ADT is an integer with predefined ranges. • several operations that can be applied to this data type (addition, subtraction, multiplication, division and so on) 3 Integer ADT ….. -3,-2,-1,0,1,2,3…. Data - Number - Positive / Negative Operations - Addition - Subtraction - Multiplication - Division Integer ADT
- 4. Abstract Data Types (ADT) ADT Types • Complex ADT: • While several simple ADTs have been implemented, such as integer, real, character, pointer and so on, and are available for use in most languages, many useful complex ADTs are not. • We need some additional ADTs that should be created and stored in the library of the computer to be used. • Example: • List, Set, Graph, Stack, Queue,etc., 4
- 5. Abstract Data Types (ADT) Data - Number - Positive / Negative Operations - Addition - Subtraction - Multiplication - Division Integer ADT Data Sequence of elements Operations Insert - Find - Delete - Next - Previous - Make Empty - Print list List ADT Simple ADTs Complex ADTs 5
- 6. List ADT • List is a complex abstract data type that represents a countable number of ordered values. • It is an ordered collection of items of some element type. • It is a widely used data structure for applications which do not need random access. • It is basically of the following form : Note: – A1 - First Element of the list. – N - Size of the list. – Position of is Ai is i. – Ai+1 succeeds Ai. – Ai-1 precedes Ai. A1,A2…….AN(N>=0) 6