510 likes | 651 Views
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. Computer Programming and Software Engineering.
E N D
Chapter 12 Computer Programming 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
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
Computer Programming and Software Engineering Chapter 12: Computer Programming
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
Programming Languages and Paradigms • First-generation languages • Second-generation languages • Third-generation languages Chapter 12: Computer Programming
Programming Languages and Paradigms • Fourth-generation languages • Fifth-generation languages • The Programming Paradigm Chapter 12: Computer Programming
Programming Languages and Paradigms 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
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
Program Coding A text editor such as Notepad allows programmers to enter lines of code using a familiar word processing interface. Chapter 12: Computer Programming
Program Coding • VDE (visual development environment) • Form design grid • Control • Properties • Event • Event-handling code 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. Chapter 12: Computer Programming
Program Coding Chapter 12: Computer Programming
Program Testing and Documentation • A computer program must be tested • Program errors include • Syntax errors • Runtime errors • Logic errors • Debugger Chapter 12: Computer Programming
Program Testing and Documentation • Remarks/Comments Chapter 12: Computer Programming
Programming Tools • SDK (software development kit) • IDE (integrated development environment) Chapter 12: Computer Programming
Programming Tools • Component • API • C and C++ are the most popular programming languages Chapter 12: Computer Programming
Procedural Programming • Algorithms • Expressing an Algorithm • Sequence, Selection, and Repetition Controls • Procedural Languages and Applications 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
Algorithms Chapter 12: Computer Programming
Expressing an Algorithm • Pseudocode Chapter 12: Computer Programming
Expressing an Algorithm • Flowchart The pizza program flowchart illustrates how the computer should proceed through the instructions in the final program. Chapter 12: Computer Programming
Expressing an Algorithm • Perform a walkthrough to make sure your algorithm works Chapter 12: Computer Programming
Sequence, Selection, and Repetition Controls • Sequence control structure Executing a GOTO command directs the computer to a different part of the program. Chapter 12: Computer Programming
Sequence, Selection, and Repetition Controls • Subroutines, procedures, and functions Chapter 12: Computer Programming
Sequence, Selection, and Repetition Controls • Selection control structure The computer executes a decision indicated on the flowchart by the question in the diamond shape. Chapter 12: Computer Programming
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. Chapter 12: Computer Programming
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
Object-Oriented Programming • Objects and Classes • Inheritance • Methods and Messages • Object-oriented Program Structure • Object-oriented Languages and Applications Chapter 12: Computer Programming
Objects and Classes • Object • Class Chapter 12: Computer Programming
Inheritance • What is inheritance? • Superclass • Subclass • Class hierarchy 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
Object-Oriented Program Structure Chapter 12: Computer Programming
Object-Oriented Program Structure Chapter 12: Computer Programming
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. Chapter 12: Computer Programming
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
Declarative Programming • The Declarative Paradigm • Prolog Facts • Prolog Rules • Input Capabilities • Declarative Languages and Applications Chapter 12: Computer Programming
The Declarative Paradigm • Attempts to describe a problem without specifying exactly how to arrive at a solution Chapter 12: Computer Programming
Secure Programming • Black Hat Exploits • Secure Software Development • Mitigation 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
Black Hat Exploits 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 Chapter 12: Computer Programming
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
Secure Software Development Chapter 12: Computer Programming
Secure Software Development • An attack tree is a hierarchical diagram of potential attacks against a system Chapter 12: Computer Programming
Secure Software Development • Defensive programming (AKA secure programming) • Source code walkthroughs • Simplification • Filtering input Chapter 12: Computer Programming
Secure Software Development • Signed code 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 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