1. Programming Process
The programmer’s job can be broken down into six programming steps:
Understand the problem
Plan the logic
Code the program
Translate the program into machine language
Test the program
Put the program into production

2. Understand the Problem
Programmers must first understand what it is the user wants
To understand the problem, you must analyze it
Really understanding the problem may be one of the most difficult aspects of programming
The description of what the user needs may be vague
The user may not even really know what he or she wants
Users who think they know what they want frequently change their minds after seeing sample output

3. Understand the Problem
Analysis & Really Understanding
Example
To invite some people, I need the list of people who work during five more years.
Definite problem or ambiguous problem ?

4. Understand the Problem
Analysis & Really Understanding
Example
To invite some people, I need the list of people who work during five more years.
Definite problem or ambiguous problem ?
Ambiguous problem
Full-time or part-time worker or both of them ?
Regular employee or contract employee ?
Which type of list ?
A good programmer is often part counselor, part detective

5. Programming Process
The programmer’s job can be broken down into six programming steps:
Understand the problem
Plan the logic
Code the program
Translate the program into machine language
Test the program
Put the program into production

6. Plan the Logic
Programmer plans the steps to the program, deciding what steps to include and how to order them
Example
Planning tour
Planning party
The two most common tools
flowcharts : pictorial representation
Pseudocode : English-like representation

7. Plan the Logic Flowcharts
A pictorial representation of the logical steps it takes to solve a problem.
Uses Standardized Symbols
Utilize Formula Notation
Typically Read from Top to Bottom or from
Left to Right on a Page

8. Plan the Logic Basic flowchart symbols Start/Stop (Terminator) Process
(Rectangle)
Input/Output
(Parallelogram)
Decision
(Diamond)
Connector
(Circle)
Flowlines
(Arrows)
Predefined Process
(Rectangle)

9. Sequence, Selection, Repetition
entrance
entrance
entrance
exit
exit
exit

10. Plan the Logic Pseudocode
An English-like representation of the logical steps it takes to solve a problem
pseudo – a prefix that means false
Short English-Like Statements
Not Standardized
Proper use of indentation
Example
start
get InputNumber
compute calculatedAnswer as InputNumber times 2
print calculatedAnswer
stop

11. Programming Process
The programmer’s job can be broken down into six programming steps:
Understand the problem
Plan the logic
Code the program
Translate the program into machine language
Test the program
Put the program into production

12. Code the program
Writing the program in one of more than 400 programming languages
Pascal, Fortran, C, C++, Java…..
Concentrate on the syntax of the language
Exact instruction, symbol, …. ?
Some very experienced programmers
successfully combining the logic planning and the actual instruction writing, or coding of the program, in one step
Writing a post card
Writing a cinema scenario

13. Code the program
Which is harder: Planning the Logic or Coding the Program?
Example
Planning the logic :Planning mystery novel
Coding the program : Writing English or Spanish based on the original scenario.
Who gets more annual salary ?

14. Programming Process
The programmer’s job can be broken down into six programming steps:
Understand the problem
Plan the logic
Code the program
Translate the program into machine language
Test the program
Put the program into production

15. Translate the Program Objective Need to compiler or interpreter
Each computer knows only one language, Machine Language.
High-level Languages must be translated into Machine Language
Need to compiler or interpreter
Compiler catches every syntax error.
When writing a program, a programmer might need to recompile the code several times
An executable program is created only when the code is free of syntax errors

16. Translate the Program
Creating an executable program

17. Programming Process
The programmer’s job can be broken down into six programming steps:
Understand the problem
Plan the logic
Code the program
Translate the program into machine language
Test the program
Put the program into production

18. Test the Program Why does it need to be tested ? Test Example
Syntax Errors : by compile
Logical Errors : by test
Test
Executing the program with some sample data
Seeing whether or not the results are logically correct.
being tested with many sets of data carefully
Example
Logically incorrect
start
get InputNumber
compute calculatedAnswer as InputNumber times 20
print calculatedAnswer
stop

19. Programming Process
The programmer’s job can be broken down into six programming steps:
Understand the problem
Plan the logic
Code the program
Translate the program into machine language
Test the program
Put the program into production

20. Put the program into the production
Once the program is tested adequately, it is ready for the organization to use.
Putting the program into production might mean simply running the program once if it was written to satisfy a user’s request for a special list.

21. Flowchart & Pseudocode
Flowcharts (pictorial representations) and pseudocode (English-like representations) are used by programmers to plan the logical steps for solving a programming problem
Some professional programmers prefer writing pseudocode to drawing flowcharts, because using pseudocode is more similar to writing final statements in programming language

22. Flowchart & Pseudocode
Almost every program involves the steps of input, processing, and output, necessitating some graphical way to separate them
Arithmetic operation statements are examples of processing in a flowchart, where you use a rectangle as the processing symbol containing a processing statement

23. Flowchart & Pseudocode
To represent an output statement, you use the parallelogram, which is also the same symbol used for input statements

24. Flowchart & Pseudocode
In flowcharts:
Arrows, or flowlines, connect and show the appropriate sequence of steps
A terminal symbol, or start/stop symbol, should be included at each end
Often, “start” or “begin” is used as the first terminal symbol and “end” or “stop” is used in the other
The standard terminal symbol is shaped like a racetrack; often called a lozenge, because it resembles the shape of a medicated candy lozenge you might use to soothe a sore throat
Flowlines
(Arrows)
Start/Stop
(Terminator)

25. Flowchart & Pseudocode
Complete flowchart for the program that doubles a number, and the pseudocode for the same problem
start
get InputNumber
compute calculatedAnswer
as InputNumber times 2
print calculatedAnswer
stop

26. Naming Variables Variables Example
memory locations, whose contents can vary or differ over time.
reasonable and descriptive variable names
Example
InputNumber
caluculatedAnswer
start
get InputNumber
compute calculatedAnswer as InputNumber times print calculatedAnswer
stop

27. Naming Variables Naming Rules
Every programming language has its own set of rules for naming variables.
most languages allow both letters and digits : a,b,c, 1,2,3
some languages allow hyphens and/or underscores : - _
some allow dollar signs or other special characters : $,
some allow for foreign characters : Japanese, Spanish
different languages put different limits on lengths
some languages are case sensitive, others are not : name, Name
in general, variable names may not begin with a digit : name1

28. Naming Variables Textbook Conventions – two rules:
(1) Variable names must be one word
can contain letters, digits, hyphens, underscores, with the exception of spaces.
(2) Variable names should have some appropriate meaning
Undesirable : G, u84, fred, mike, richard, pink,
Desirable : rate, name, age, count, score, index, lastName
employeeLastName, 5employeeLastName, employeeLast, empLast,
emlstnam, lastNameofTheEmployeeInQuestion, last name (x),
employeelastname,

29. Naming Variables Assignment values to variables
Whatever operation is performed to the right of the equal sign results in a value that is placed in the memory location to the left of the equal sign.
compute calculatedAnswer
as InputNumber times 2
is the same as
calculatedAnswer = InputNumber * 2

30. Naming Variables Constant Variables
A memory location, similar to a variable, except its value never changes during a program.
taxRate = .0825
Pi =
Variables
memory locations, whose contents can vary or differ over time.

31. Naming Variables Data Types – two basic types Character Numeric
Character : ‘a’ ‘b’ ‘c’ ‘d’ ‘e’
Character string : “Richard” “Michale”
Numeric
Integer : …, -3, -2, -1, 0, 1, 2, 3, ….
Floating-Point : …, -2.0, -1.5, -1, -0.5, 0, 0.5, 1.0, ….

32. calculatedAnswer=InputNumber*2
Ending a Program
Infinite loop
start
get InputNumber
compute calculatedAnswer
as InputNumber times 2
print calculatedAnswer
………
stop
start
get
InputNumber
calculatedAnswer=InputNumber*2
Print
calculatedAnswer

33. Ending a Program
An infinite loop is a repeating flow of logic with no end
To end the program,
set a predetermined value for inputNumber that means “Stop the program!”
The program can then test any incoming value for inputNumber and, if it is a 0, stop the program
Testing a value is also called making a decision
Represented in flowchart by diamond shape called a decision symbol

34. Ending a Program Decision symbol start start get InputNumber get
Yes
inputNumber
= 0 ?
inputNumber
= 0 ?
stop No
calculatedAnswer=InputNumber*2
calculatedAnswer=InputNumber*2
Print
calculatedAnswer
Print
calculatedAnswer

35. Ending a Program Dummy value
A pre-selected value that stops the execution of a program is often called a dummy value since it does not represent real data, but just a signal to stop
Sometimes, such a value is called a sentinel value because it represents an entry or exit point, like a sentinel who guards a fortress

36. Using a Connector
If a flowchart has six processing steps and a page provides room for only three, you might represent the logic as shown below:
On-page connector symbol
Off-page connector symbol

37. Evolution of Programming Technique
Currently, there are two major techniques used to develop programs and their procedures
Procedural programming focuses on the procedures that programmers create
Object-oriented programming, focuses on objects, or “things”, and describes their features, or attributes, and their behaviors

38. Summary A programmer’s job involves six steps:
Understanding the problem
Planning the logic
Coding the problem
Translating the program into machine language
Testing the program
Putting the program into production
When programmers plan the logic for a solution to a programming problem, they often use flowcharts or pseudocode

39. Summary Testing a value involves making a decision
Most programming languages use the equal sign to assign values to variables
Procedural and object-oriented programmers approach program problems differently