Abstract Data Types, Elementary Data Structures and Arrays Lecture 01 Abstract Data Types, Elementary Data Structures and Arrays

Abstract data Types Abstract Data Type is an organized collection of information and a set of operations used to manage that information. e.g. Whole numbers (integers) and arithmetic operators for addition, subtraction, multiplication and division. e.g. Flight reservation Basic operations: find empty seat, reserve a seat, cancel a seat assignment Data, operations, and relations are studied independent of implementation. What not how is the focus. Superior Uni- DSA2014 BSSE

ADT and DS A data structure is the physical implementation of an ADT. Abstract data type a new type describes properties and operations Each ADT operation is defined by its inputs and outputs Collection of elements or we can say information. Logical form A data structure is the physical implementation of an ADT. Each operation associated with the ADT is implemented by one or more subroutines in the implementation. How collection is stored in memory Physical/ Concrete form Stack is ADT with push, pop operations, but can we say about stack data structure if I mean I used stack implemented as an array in my algorithm? And why heap isn't ADT Superior Uni- DSA2014 BSSE

Data Type ADT: Type Data Items: Operations Logical Form Data Structure: Storage Space Subroutines Data Items: Physical Form 4 Superior Uni- DSA2014 BSSE

Arrays An array is a series of elements of the same type placed in contiguous memory locations that can be individually referenced by adding an index to a unique identifier The lowest address corresponds to the first element and the highest address to the last element. One dimensional array Two Dimensional array Superior Uni- DSA2014 BSSE

type arrayName [ arraySize ]; double balance[10]; Declaring Arrays: type arrayName [ arraySize ]; double balance[10]; Initializing array double balance[5] = {1000.0, 2.0, 3.4, 17.0, 50.0}; Accessing Array Elements: double salary = balance[9]; Superior Uni- DSA2014 BSSE

Superior Uni- DSA2014 BSSE

Superior Uni- DSA2014 BSSE

Superior Uni- DSA2014 BSSE

2D array Simplest form of multidimensional array A two-dimensional array can be think as a table, which will have x number of rows and y number of columns Most high level languages support arrays with more than one dimension. 2D arrays are useful when data has to be arranged in tabular form. Higher dimensional arrays appropriate when several characteristics associated with data. Superior Uni- DSA2014 BSSE

Declaring 2D Array type arrayName [ x ][ y ]; Initializing 2D Array: int a[3][4] = { {0, 1, 2, 3} , {4, 5, 6, 7} , {8, 9, 10, 11} }; or int a[3][4] = {0,1,2,3,4,5,6,7,8,9,10,11}; Accessing Two-Dimensional Array Elements: int val = a[2][3]; Superior Uni- DSA2014 BSSE

Superior Uni- DSA2014 BSSE