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Chapter 2- Visual Basic Schneider 1

Chapter 2

Problem Solving

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Chapter 2- Visual Basic Schneider 2

Outl ine and Objective

Program Development Cycle

Programming Tools

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Chapter 2- Visual Basic Schneider 3

Programming Languages:

Machine Language

Assembly Language

High level Language

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Chapter 2- Visual Basic Schneider 4

Machine Language

The fundamental language of the computers

processor, also called Low Level Language.

All programs are converted into machine languagebefore they can be executed.

Consists of combination of 0s and 1s that

represent high and low electrical voltage.

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Chapter 2- Visual Basic Schneider 5

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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Chapter 2- Visual Basic Schneider 6

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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Chapter 2- Visual Basic Schneider 7

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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Chapter 2- Visual Basic Schneider 8

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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Chapter 2- Visual Basic Schneider 9

Programming Tools:

Flowchart

Pseudocode

Hierarchy Chart (Structure chart)

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Chapter 2- Visual Basic Schneider 10

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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Chapter 2- Visual Basic Schneider 11

Continue flowchart

Programmer prepares flowchart before

coding.

Most common flowchart symbols are:

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Chapter 2- Visual Basic Schneider 12

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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Chapter 2- Visual Basic Schneider 13

Example of Flowchart:

Start

Initialize Counter =1

and sum to 0

Are there more data

Get next grade

Increment counter

Add grade to sum

Yes

No

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Chapter 2- Visual Basic Schneider 14

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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Chapter 2- Visual Basic Schneider 15

What is a Pseudocode?

A program design technique that uses

English words.

Has no formal syntactical rules.

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Chapter 2- Visual Basic Schneider 16

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 / CounterDisplay average

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Chapter 2- Visual Basic Schneider 17

What is a Hierarchy Chart?

Shows the overall programs 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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Chapter 2- Visual Basic Schneider 18

Example of Hierarchy Chart:

Class average

Program

GetGrade

CalculateAverage

ComputeSum

DisplayAverage