Transcript Programming Languages

Chapter 2
Problem Solving
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Outline and Objective
Program Development Cycle
Programming Tools
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Programming Languages:
• Machine Language
• Assembly Language
• High level Language
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Machine Language
• The fundamental language of the computer’s
processor, also called Low Level Language.
• All programs are converted into machine language
before they can be executed.
• Consists of combination of 0’s and 1’s that
represent high and low electrical voltage.
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Assembly Language
• A low level language that is similar to
machine language.
• Uses symbolic operation code to represent
the machine operation code.
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High Level Language
• Computer (programming) languages that
are easier to learn.
• Uses English like statements.
• Examples are C ++, Visual Basic, Pascal,
Fortran and …....
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Program Development Cycle:
1. Analyze: Define the problem
2. Design: Plan the solution to the problem
3. Choose the Interface: Select the objects
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Program Development Cycle:
4. Code: Translate the algorithm into a
programming language.
5. Debug and Test: Locate and remove any
errors in the program.
6. Complete the Documentation: Organize all
the materials that describe the program.
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Programming Tools:
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Flowchart
Algorithms
Pseudocode
Hierarchy Chart (Structure chart)
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What is a flowchart?
• Logic diagram to describe each step that the
program must perform to arrive at the
solution.
• A popular logic tool used for showing an
algorithm in graphics form.
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Continue flowchart
• Programmer prepares flowchart before
coding.
• Most common flowchart symbols are:
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Purpose of Flowcharting:
• An aid in developing the logic of a program.
• Verification that all possible conditions have
been considered in a program.
• Provides means of communication with
others about the program.
• A guide in coding the program.
• Documentation for the program.
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Example of Flowchart:
Start
Initialize Counter =1
and sum to 0
Are there more data
No
Yes
Get next grade
Increment counter
Add grade to sum
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Desk Checking
• The process of testing the flowchart with different
data as input, and checking the output.
• The test data should include nonstandard data as
well as typical data.
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ALGORITHMS
• Used to develop the step by step
instructions for a computer program or
Object event.
• Algorithms are used to develop the logic of
a program or Object event.
• Also aids in identifying variables needed in
a program or event.
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Example Algorithm
EXAMPLE HERE
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What is a Pseudocode?
• A program design technique that uses
English words.
• Has no formal syntactical rules.
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Example of Pseudocode:
• Determine the average grade of a class:
Do while there are more data
Get the next Grade
Add the Grade to the Sum
Increment the Counter
Loop
Compute average = Sum / Counter
Display average
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What is a Hierarchy Chart?
• Shows the overall program’s structure.
• Describes what each part, or module, of the
program does.
• Also how each module relates to other
modules in the program.
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Example of Hierarchy Chart:
Class average
Program
Get
Grade
Compute
Sum
Calculate
Average
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Display
Average
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