1. Chapter 12: Computer Programming

2. Chapter 12: Computer Programming
Programming Basics
Computer Programming and Software Engineering
Programming Languages and Paradigms
Program Planning
Program Coding
Program Testing and Documentation
Programming Tools
Chapter 12: Computer Programming

3. Computer Programming and Software Engineering
The instructions that make up a computer program are sometimes referred to as code
Programs can have millions of lines of code
Chapter 12: Computer Programming

4. Computer Programming and Software Engineering
Figure 12-1
Chapter 12: Computer Programming

5. Programming Languages and Paradigms
Programming languages are made up of keywords and grammar rules designed for creating computer instructions
Low-level languages
High-level languages
Chapter 12: Computer Programming

6. Programming Languages and Paradigms
First-generation languages
Second-generation languages
Third-generation languages
Chapter 12: Computer Programming

7. Programming Languages and Paradigms
Fourth-generation languages
Fifth-generation languages
The Programming Paradigm
Chapter 12: Computer Programming

8. Programming Languages and Paradigms
Figure 12-8
Chapter 12: Computer Programming

9. Chapter 12: Computer Programming
Program Planning
The problem statement defines certain elements that must be manipulated to achieve a result or goal
You accept assumptions as true to proceed with program planning
Known information helps the computer to solve a problem
Variables vs. constants
Chapter 12: Computer Programming

10. Chapter 12: Computer Programming
Program Planning
Problem statement:
Assuming that there are two pizzas to compare, that both pizzas contain the same toppings, and that the pizzas could be round or square, and given the prices, shapes, and sizes of the two pizzas, the computer will print a message indicating which pizza has the lower price per square inch
Chapter 12: Computer Programming

11. Chapter 12: Computer Programming
Program Coding
A text editor such as
Notepad allows programmers
to enter lines of code using a familiar word processing interface.
Figure 12-11
Chapter 12: Computer Programming

12. Chapter 12: Computer Programming
Program Coding
VDE (visual development environment)
Form design grid
Control
Properties
Event
Event- handling code
Figure 12-12
Chapter 12: Computer Programming

13. Chapter 12: Computer Programming
Program Coding
Controls, such as the
Best Deal button, can be
selected by a programmer
from a properties list. Here a programmer is selecting the background color for the Best Deal button.
Figure 12-13
Chapter 12: Computer Programming

14. Chapter 12: Computer Programming
Program Coding
Figure 12-14
Chapter 12: Computer Programming

15. Program Testing and Documentation
A computer program must be tested
Program errors include
Syntax errors
Runtime errors
Logic errors
Debugger
Chapter 12: Computer Programming

16. Program Testing and Documentation
Remarks/Comments
Figure 12-16
Chapter 12: Computer Programming

17. Chapter 12: Computer Programming
Programming Tools
SDK (software development kit)
IDE (integrated development environment)
Chapter 12: Computer Programming

18. Chapter 12: Computer Programming
Programming Tools
Component
API
C and C++ are the most popular programming languages
Chapter 12: Computer Programming

19. Procedural Programming
Algorithms
Expressing an Algorithm
Sequence, Selection, and Repetition Controls
Procedural Languages and Applications
Chapter 12: Computer Programming

20. Chapter 12: Computer Programming
Algorithms
What is an algorithm?
Record steps to solve the problem
Specify how to manipulate information
Specify a solution
Chapter 12: Computer Programming

21. Chapter 12: Computer Programming
Algorithms
Figure 12-21
Chapter 12: Computer Programming

22. Expressing an Algorithm
Pseudocode
Figure 12-22
Chapter 12: Computer Programming

23. Expressing an Algorithm
Flowchart
The pizza program flowchart
illustrates how the computer
should proceed through the
instructions in the final program.
Figure 12-23
Chapter 12: Computer Programming

24. Expressing an Algorithm
Perform a walkthrough to make sure your algorithm works
Figure 12-24
Chapter 12: Computer Programming

25. Sequence, Selection, and Repetition Controls
Sequence control structure
Executing a GOTO command
directs the computer to a different
part of the program.
Figure 12-25
Chapter 12: Computer Programming

26. Sequence, Selection, and Repetition Controls
Subroutines, procedures, and functions
Figure 12-26
Chapter 12: Computer Programming

27. Sequence, Selection, and Repetition Controls
Selection control structure
The computer executes a decision
indicated on the flowchart by the question in the diamond shape.
Figure 12-27
Chapter 12: Computer Programming

28. Sequence, Selection, and Repetition Controls
Repetition control structure
To execute a loop, the computer
repeats one or more commands until some condition indicates that the looping should stop.
Figure 12-28
Chapter 12: Computer Programming

29. Procedural Languages and Applications
Popular procedural languages include FORTRAN, COBOL, FORTH, APL, ALGOL, PL/1, Pascal, C, Ada, and BASIC
The procedural approach is best used for problems that can be solved by following a step-by-step algorithm
Produces programs that run quickly and efficiently
Chapter 12: Computer Programming

30. Object-Oriented Programming
Objects and Classes
Inheritance
Methods and Messages
Object-oriented Program Structure
Object-oriented Languages and Applications
Chapter 12: Computer Programming

31. Chapter 12: Computer Programming
Objects and Classes
Object
Class
Figure 12-30
Chapter 12: Computer Programming

32. Chapter 12: Computer Programming
Inheritance
What is inheritance?
Superclass
Subclass
Class hierarchy
Figure 12-33
Chapter 12: Computer Programming

33. Chapter 12: Computer Programming
Methods and Messages
Method
Collect input, perform calculations, etc.
A method is activated by a message
Can be defined along with the class they affect
Polymorphism
Chapter 12: Computer Programming

34. Object-Oriented Program Structure
Figure 12-39
Chapter 12: Computer Programming

35. Object-Oriented Program Structure
Figure 12-40
Chapter 12: Computer Programming

36. Object-Oriented Program Structure
When the pizza program
runs, on-screen prompts
ask for the shape, size, and
price of each pizza; then
the program displays a
message that indicates
which pizza is the best
deal.
Figure 12-41
Chapter 12: Computer Programming

37. Object-Oriented Languages and Applications
SIMULA was believed to be the first object-oriented computer language
The Dynabook project was the second major development in object-oriented languages
Popular object-oriented languages today are Ada95, C++, Visual Basic, C#, and Java
The O-O paradigm results in decreased runtime efficiency, but allows encapsulation, which hides the internal details of objects and their methods
Chapter 12: Computer Programming

38. Declarative Programming
The Declarative Paradigm
Prolog Facts
Prolog Rules
Input Capabilities
Declarative Languages and Applications
Chapter 12: Computer Programming

39. The Declarative Paradigm
Attempts to describe a problem without specifying exactly how to arrive at a solution
Chapter 12: Computer Programming

40. Chapter 12: Computer Programming
Secure Programming
Black Hat Exploits
Secure Software Development
Mitigation
Chapter 12: Computer Programming

41. Chapter 12: Computer Programming
Black Hat Exploits
Today’s operating systems, utilities, and application software are full of defects that create security holes, which are exploited by black hats
Buffer overflow
Chapter 12: Computer Programming

42. Chapter 12: Computer Programming
Black Hat Exploits
Figure 12-53
Chapter 12: Computer Programming

43. Chapter 12: Computer Programming
Black Hat Exploits
Verbose error messages can also present attackers with information about the directory location of programs or files, the structure of a database, or the layout of the program in memory
Figure 12-54
Chapter 12: Computer Programming

44. Secure Software Development
Most software security problems can be traced back to defects that programmers unintentionally introduce in software during design and development
Formal methods help programmers apply rigorous logical and mathematical models to software design, coding, testing, and verification
Threat modeling (risk analysis) – used by security designer to determine (1) what are important issues the designer cares about and (2) a description of a set of security aspects (possible attacks to consider)
Chapter 12: Computer Programming

45. Secure Software Development
Chapter 12: Computer Programming

46. Secure Software Development
An attack tree is a hierarchical diagram of potential attacks against a system
Figure 12-56
Chapter 12: Computer Programming

47. Secure Software Development
Defensive programming (AKA secure programming)
Source code walkthroughs
Simplification
Filtering input
Chapter 12: Computer Programming

48. Secure Software Development
Signed code
Figure 12-57
Chapter 12: Computer Programming

49. Chapter 12: Computer Programming
Mitigation
Despite defensive programming and other tactics to produce secure software, some defects inevitably remain undiscovered in products that end up in the consumers’ hands. When bugs are discovered, the programmer’s remaining line of defense is to produce a bug fix, or patch
Figure 12-58
Chapter 12: Computer Programming

50. Chapter 12: Computer Programming
Mitigation
Take the following steps to avoid security problems that stem from software defects
Select applications from software publishers with a good security track record
Watch for patches and apply them
Consider using open source software, which has been extensively reviewed by the programming community
Keep your firewall and antivirus software deployed and up-to-date
Chapter 12: Computer Programming

51. Chapter 12: Computer Programming
Chapter 12 Complete
Computer Programming
Chapter 12: Computer Programming