chapter 2- visual basic schneider1 chapter 2 problem solving
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Chapter 2- Visual Basic Schneider
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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:
• 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 =1and sum to 0
Are there more data
Get next grade
Increment counter
Add grade to sum
Yes
No
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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 CounterLoopCompute average = Sum / CounterDisplay 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
GetGrade
Calculate Average
Compute Sum
Display Average