Systems Analysis & Programming 10.1 Systems Development 10.2 Programming: A Five-Step Procedure Generations of Programming Languages 10.4 Programming Languages Used Today 10.5 Object-Oriented & Visual Programming 10.6 Markup & Scripting Languages Chapter10

2 Systems Development  Organizations can make mistakes, and big organizations can make really big mistakes  Murphy’s Law: Whatever can go wrong, will go wrong, and at the worst possible time  A system A collection of related components that interact to perform a task in order to accomplish a goal  Systems Development 6-phase process of gathering information about system requirements and using that to develop a new system that improves productivity Warning! Road Out!

3 Systems Development  The three kinds of “roles” (users) of a project are: Users  The new system must ALWAYS be developed in consultation with the people who will be using the completed system Management  Managers within an organization should be consulted about the system, as they control the budget and resources Technical staff  The Information Systems or IT staff must be involved so they can make sure the technology is there

4 Systems Development  Systems Analyst An information specialist who performs systems analysis, design, and implementation His or her job is to study the information and communications needs of an organization and determine what changes are needed to deliver better information to the people who need it

5 Systems Development  The 6 phases of systems analysis & design are:  Information systems are frequently revised and upgraded  Steps in the cycle often overlap

6 Systems Development  Phase 1: Conduct a preliminary investigation Conduct a preliminary analysis Propose alternative solutions  Interview people within the organization  Study what competitors are doing  Decide to leave the system as is, improve it, or develop a new system Describe costs and benefits Submit a preliminary plan with recommendations  This should be a written report  Get management approvals for next phase

7 Systems Development  Phase 2: Analyze the system Gather data  Interview employees and managers  Develop, distribute, analyze questionnaires  Review current written documents  Observe people and processes at work Analyze the data  Use system modeling tools  Create a data flow diagram to show how data flows through the system Write a report and get approvals for next phase  Document how the current system works  Document problems with the current system  Describe the requirements for the new system

8 Systems Development  Phase 3: Design the system Notice that you don’t design the new system until you have done phase 2 since that establishes the requirements it must meet! Do a preliminary design  Often involves prototyping Do a detail design, showing:  Input requirements  Output requirements  Storage requirements  Processing requirements  System controls  Backup Write a report and get approvals for next phase

9 Systems Development  Phase 4: Develop the system Develop or acquire the software Acquire and integrate the hardware Test the system  Unit testing  Systems testing with both analysts and end- users  End-user testing is critical, as they don’t know the software and will show the developers where they forgot something

10 Systems Development  Phase 5: Implement the system Choose a strategy to convert to the new system  Direct implementation  Parallel implementation  Phased implementation  Pilot implementation Train the users  Document the system  Give classes or train the trainers

11 Systems Development  Phase 6: Maintain the system Perform periodic evaluations Make changes to the system based on new conditions Document those changes

12 Programming: A Five-Step Procedure  A program is a list of instructions that the computer must follow to process data into information  The five steps are 1.Clarify/define the problem 2.Design the program 3.Code the program 4.Test the program 5.Document and maintain the program

13 5 Generations of Programming Languages  1945 – 1 st Generation – Machine Language The basic language of the computer – all zeros and ones Each CPU architecture had a different machine language

14 5 Generations of Programming Languages  1945 – 1 st Generation – Machine Language  Mid-1950s – 2 nd Generation – Assembly Language Mnemonic version of machine language Faster to program in than machine language Each CPU architecture had a different assembler

15 5 Generations of Programming Languages  1945 – 1 st Generation – Machine Language  Mid-1950s – 2 nd Generation – Assembly Language  Mid-1950s to 60s – 3 rd Generation – High- level Languages (procedural languages) such as FORTRAN, COBOL, BASIC, C These languages are portable (the same across all CPUs) The programmer writes, then interprets or compiles the programs The compiler or interpreter translates the code into the CPU-specific assembler

16 5 Generations of Programming Languages  1945 – 1 st Generation – Machine Language  Mid-1950s – 2 nd Generation – Assembly Language  Mid-1950s to 60s – 3 rd Generation – High-level Languages (procedural languages) such as FORTRAN, COBOL, BASIC, C  Early 1970s – 4 th Generation – Problem-oriented Languages such as SQL, Intellect, NOMAD, FOCUS Easier to program in than 3 rd generation languages Three types are:  Report generators  Query languages  Application generators

17 5 Generations of Programming Languages  1945 – 1 st Generation – Machine Language  Mid-1950s – 2 nd Generation – Assembly Language  Mid-1950s to 60s – 3 rd Generation – High-level Languages (procedural languages) such as FORTRAN, COBOL, BASIC, C  Early 1970s – 4 th Generation – Problem-oriented Languages such as Intellect, NOMAD, FOCUS  Early 1980s – 5 th Generation – Natural Languages Programming languages that use human language to give people a more natural connection with computers Part of the field of artificial intelligence

18 Programming Languages Used Today

19 Object-Oriented What Is an Object?  Objects are key to understanding object-oriented technology.  Look around right now and you'll find many examples of real-world objects: your dog, your desk, your television set, your bicycle.

20 Object-Oriented What Is an Object?  Real-world objects share two characteristics: They all have state and behavior.  Dogs have state (name, color, breed, hungry) and  behavior (barking, fetching, wagging tail).  Identifying the state and behavior for real-world objects is a great way to begin thinking in terms of object-oriented programming.

21 Object-Oriented What Is an Object?  Software objects are conceptually similar to real-world objects: they too consist of state and related behavior.  An object stores its state in properties (fields, attributes or variables in some programming languages)  An object exposes its behavior through methods (functions in some programming languages).

22 Object-Oriented What Is a Method?  Methods operate on an object's internal state and serve as the primary mechanism for object-to- object communication.  Hiding internal state and requiring all interaction to be performed through an object's methods is known as data encapsulation — a fundamental principle of object-oriented programming.

23 Object-Oriented & Visual Programming  In Object oriented Programming (OOP) data and processing instructions are combined into an object that can be reused Object  Self-contained module consisting of reusable code Message  The instruction received by the object indicating it is time to perform an action Method  The processing instructions within the object to perform the specified action

24 Object-Oriented & Visual Programming  Black Box Objects are like a black box in that the actions and the objects are specified, but the methods used are internal to the object This means the programmer that uses an object does not need to know how the program inside the object does what it does For example, Microsoft Excel is like an object  Most of us use Excel without understanding what the programmers at Microsoft did to make Excel work  If we had to know that, it would take a lot longer to learn how to use Excel!  Programmers who use objects can write programs a lot faster, because objects save so much work

25 Object-Oriented & Visual Programming  3 basic concepts of OOP Encapsulation  One object contains (encapsulates) both State Data (properties) Relevant processing instructions or behavior (methods) Inheritance  One object can be used as the foundation for other objects  Objects can be arranged in hierarchies – classes and subclasses  Objects can inherit actions and attributes from each other Polymorphism  Allows a single definition to be used with different data types and different functions  Means a message produces different results depending on the object it is sent to

26 Object-Oriented & Visual Programming Doors Have a Handle open close Patio doors Have a slider slide open slide closed Front doors Have locks Car doors Have locks Have windows The “Door” class Actions performed by a door (behavior) Subclasses of doors inherit from the door class, but also have their own unique actions and attributes Notice we only list the actions & attributes when they differ from those of class Example of Inheritance Hierarchy with Specialization

27 Object-Oriented & Visual Programming  Visual Basic is an example of visual programming Using a mouse, the programmer drags and drops objects on screen The objects are arranged to make up the graphical user interface for the program being written By double-clicking on those objects, the programmer can get into a coding window and write the programs to control the actions and behaviors of those objects This makes it fast and easy to build prototype user interfaces and get end-user approval before doing a lot of programming