1. Fundamental Concept - Data Structures using C++ by Varsha Patil
- 1. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 1
- 2. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil Understand the well-defined, clear, and simple approach of program design Learn fundamental aspects of algorithm and its characteristics Learn basic concepts such as data, data type, data object, data structure, etc. Know the power of Abstract Data Type (ADT) Study about Software Development Life Cycle (SDLC) 2
- 3. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 3 Program Data Computer Output Fig 1: Processing a Program
- 4. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 4 Machine Language Assembly Language High-level Language
- 5. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil OOP is used to model the real world through objects Object-oriented decomposition views software as a set of well-defined objects that model entities in the application domain These objects interact with each other to form a software system 5
- 6. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil Data Data Type Data Object Data structure Abstract Data Types (ADT) 6
- 7. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 7 Data is nothing but a piece of information Data input, data manipulation (or data processing) and data output are the themes of computer The address of the ith element is calculated by the following formula Atomic Data Composite Data
- 8. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 8 Data type is a term that specifies the type of data that a variable may hold in the programming language Built-in Data Types User Defined Data Types
- 9. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 9 A Data Object represents a container for data values a place where data values may be stored and later retrieved Data Object is runtime instance of data structure
- 10. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 10 A combination of elements each of which is either a data type or another data structure and A set of associations or relationships (structures) involving the combined elements A data structure is a set of domains D, a designated domain d Î D, a set of function F, and a set of axioms A The triple (D, F, A) denotes the data structure d and it will usually be written as d A Data Structure is
- 11. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 11 An Abstract Data Type is a data declaration packaged together with the operations that are meaningful for the data type Abstract Data Type includes declaration of data, implementation of operations, and encapsulation of data and operations
- 12. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil Primitive and Non-Primitive Data Structures Linear and Non-linear Data Structures Static and Dynamic Persistent and Ephemeral Data Structures Sequential Access and Direct Access Data Structures 12
- 13. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 13 A Data Structure is said to be linear if its elements form a sequence or a linear list Linear Data Structure, every data element has unique successor and unique predecessor
- 14. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 14 In non-linear data structures, every data element may have more than one predecessor as well as successor Elements do not form any particular linear sequence
- 15. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 15 Characteristics of Algorithm Algorithmic Design Tools Pseudo Code Flow chart
- 16. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 16 The step-by-step solution is called an Algorithm Algorithm is independent of computer system and programming language The real world performance of any software depends on two things The algorithm chosen, and The suitability and efficiency of various layers of implementation
- 17. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 17 Input Output Unambiguous Steps Finiteness Effectiveness
- 18. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil How to devise algorithms How to validate algorithms How to analyze algorithms 18
- 19. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil Pseudo code Notations Algorithm Header Purpose Conditions and Return Statement Statement Numbers Variables Statement Constructs Sub Algorithms 19
- 20. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil Sequence Decision Repetition 20
- 21. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 21 Figure 2: Sequence construct
- 22. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 22 Figure 3: Decision Construct If a condition is true, Then Else Algorithm Purpose :Comparing two numbers Pre: None Post: None Return: None 1) Read two numbers Num1 and Num2 2) If Num1 > Num2 a. Then Print Num1 b. Else Print Num2 3) Stop Series of Actions Series of Actions Example
- 23. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 23 Figure 3: Decision Construct If a condition is true, Then Algorithm Purpose :Comparing two numbers Pre: None Post: None Return: None 1) Read two numbers Num1 and Num2 2) If Num1 > Num2 a. Then Print Num1 b. Else Print Num2 3) Stop Series of Actions Series of Actions Example
- 24. 24 Data Structures in C++ by Dr. Varsha Patil Oxford University Press © 2012 Figure 4: Repetition Construct
- 25. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 25 Relationship between Data, Data Structures, and Algorithms A data structure represents a set of data items with a specific relationship between them. The success of a software project often depends upon the choices made in the representation of data and algorithms designed to process the data The proper choice of a data structure can be a key point in the design of many algorithms
- 26. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 26 Specification Implementation
- 27. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 27 A very effective tool to show the logic flow of a program A flow chart is a pictorial representation of an algorithm. It hides all of the details of an algorithm by giving the picture; It shows how the algorithm flows from beginning to end
- 28. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 28 Figure 5: Flow chart for adding three numbers
- 29. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 29 Complexity of Algorithms Space Complexity Time Complexity Computing Time Complexity of Algorithm Big-O Notation
- 30. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 30 Amount of computer memory required during the program execution, as a function of the input size Space complexity measurement which is space requirement of an algorithm can be done at two different times: Compile time and Execution time
- 31. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 31 Compile Time Space Complexity is defined as the storage requirement of a program at compile time Space Complexity = Space needed of compile time
- 32. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 32 If program is recursive or uses dynamic variables or dynamic data structure then there is a need to determine space complexity at runtime The memory requirement is summation of the Program Space Data Space And Stack Space
- 33. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 33 Time Complexity of an algorithm is a measure of how much time is required to execute an algorithm for a given number of inputs Time Complexity T(P) is the time taken by program P and the sum of the compile and execution time
- 34. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 34 Worst Case Complexity of the algorithm is the function defined by the maximum number of steps taken on any instance of size n Best Case Complexity of the algorithm is the function defined by the minimum number of steps taken on any instance of size n Average Case Complexity of the algorithm is the function defined by an average number of steps taken on any instance of size n
- 35. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 35 The total time taken by the algorithm or program is calculated using the sum of the time taken by each of executable statement in algorithm or program Time required by each statement depends on Time required for executing it once Number of times the statement is executed
- 36. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 36 Software Engineering Software Engineering is the establishment and use of sound engineering methods and principles to obtain reliable software that works on real machines A fundamental concept in Software Engineering is the Software Development Life Cycle (SDLC)
- 37. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 37 Software Engineering Analysis Phase Design Phase Implementation Phase Testing Phase Verification
- 38. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 38 Figure 6: System Development Phases Software Engineering
- 39. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 39 Analysis Phase Define the User Define the Needs Define the Requirements Define the Methods
- 40. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 40 Design Phase Modularity The design phase uses a very well- established principle called Modularity The whole package is divided into small modules
- 41. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 41 Implementation Phase Tools Flowchart Pseudo Code Coding
- 42. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 42 Testing Phase Testing Phase Once the programs have been written, they must be tested. There are two types of testing: Black Box White Box
- 43. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 43 Verification Program verification is a process to prove that the program does what it is intended to do It is said that 'even verification must be verified' This means, along with system, tests made are to be verified Also, every software quality must be verified
- 44. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 44 KEY TERMS DATA DATA TYPE DATA OBJECT DATA STRUCTURE ABSTRACT DATA TYPE LINEAR DATA STRUCUTRE NON LINEAR DATA STRUCTURE ALGORITHM ASSEMBLER COMPILER PROGRAM PSEUDOCODE FLOWCHART SOFTWARE ENGINEERING
- 45. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 45 Summary Computer is a programmable data processing machine that accepts input; instructions to process input (program) and generates required output. Data and program are stored in computer’s memory. A program is written in computer’s language. The art of programming consists of designing or choosing algorithms and expressing them in a programming language. An algorithm is a stepwise description of action which leads the problem from its start state to its goal state One of the common tools used to define algorithms is pseudo code. Pseudo code is an English-like representation of the code required for an algorithm. It is part of English, part structured code A very effective tool to show the logic flow of a program is the flow chart. A flow chart is a pictorial representation of an algorithm. It hides all of the details of an algorithm by giving the picture; it shows how the algorithm flows from beginning to end Program verification is a process to prove that the program does what it is intended to do
- 46. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 46 Summary Engineering is the establishment and use of sound engineering methods and principles to obtain reliable software that works on real machines A data structure represents a set of data items with a specific relationship between them. The success of a software project often depends upon the choices made in the representation of data and algorithms designed to process the data. The proper choice of a data structure can be a key point in the design of many algorithms
- 47. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 47 Summary The various types Software Engineering is the establishment and use of sound engineering methodologies and the principle to writing reliable of data structures are: Primitive and Non-primitive data structures Linear and Non-linear data structures Static and Dynamic data structures Persistent and Ephemeral data structures Sequential and Direct access data structures
- 48. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 48 Summary There is an intimate relationship between the structuring of data, and analysis of algorithms. In fact, a data structure and an algorithm should be thought of as a one single unit, neither one along making sense without the other. · Algorithms heavily depend on the organization of data There can be several organizations of data and/or algorithms for a given problem. Difficulty lies in deciding which algorithms is the best. We can compare one algorithm with other and choose the best. For comparison we need to analyze algorithms. Analysis involves measuring the performance of an algorithm in terms of time and space complexity
- 49. Oxford University Press © 2012Data Structures Using C++ by Dr Varsha Patil 49