EGR 141 Computer Problem Solving in Engineering and Computer Science

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EGR 141Computer Problem Solving in Engineering
and Computer Science

• Data Types and Variables

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Strings
[phone] Hello, this is a string! The
article Small Miracles is good This is an
example of a string in Visual Basic _ that
goes for more than one line. It can even
_ go on for three lines.
Quotes within a string
String Continuation
Empty String
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Strings
lblThetext.Text This is the caption for the
control _ called lblThetext!
String continuation
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Strings
Putting the strings together lblText.Text
Hello txtName.Text ! lblText.Text
Hello txtName.Text ! lblText2.Text Welcome
txtName.Text _ to the Grand
Hotel.
Concatenation
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Comments
Begin a comment with a mark This is a
comment lblText.Text Hello Put Hello
in the box Program Header Program
Lab 1 - Hello World Form
frmHello Programmer Robin Bank Purpose
The user can enter their name and when
they click the Show Message button
it will welcome them.
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Variable Names

• VB Rules
• lt 255 characters
• must begin with an alphabetic character
• can't contain punctuation characters (except
  underscore "_")
• must be unique within the same scope
• case insensitive
• can't be the same as a keyword

• Textbook Conventions
• be meaningful and descriptive
• use consistent abbreviations for same word
• use entire words or initial syllables
• use mixed case, with a capital letter at the
  start of each word ("camel-back notation")
• Generally between 5 and 20 characters.

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Data Types

• Data Types
• Short. A non-decimal (whole) number with a value
  in the range of -32,768 to 32,767.
• Integer. A non-decimal (whole) number with a
  value in the range of -2,147,483,648 to
  2,147,483,647.
• Long. A non-decimal (whole) number with a value
  in the range of -9,223,372,036,854,775,808 to
  9,223,372,036,854,775,807.

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Data Types

• Data Types
• Single. A floating-point (decimal) positive or
  negative number with a value in the range of up
  to 3.402823E38 (scientific notation).
• Double. A floating-point (decimal) positive or
  negative number with a value in the range of up
  to 1.79769313486232E308.
• Decimal. A decimal number with a value in the
  range of up to 79,228,162,514,264,337,593,950,335
  . without decimal precision and up to
  7.9228162514264337593543950335 with 28 places of
  decimal precision.
• String. Any number of alphabetic, numerical, and
  special characters.
• Date. Dates in the range between January 1, 0001
  to December 31, 9999 and times in the range
  between 00000 to 235959.
• Boolean. The value True or False.

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Data Types

• Data Types
• String. Any number of alphabetic, numerical, and
  special characters.
• Date. Dates in the range between January 1, 0001
  to December 31, 9999 and times in the range
  between 00000 to 235959.
• Boolean. The value True or False.

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Declarations
Dim MyNumber As Long Dim MyDecimal As Double Dim
NumberA, NumberB, NumberC As Long Dim message As
String Dim fName, lName As String Const PI As
Double 3.14159
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Declarations
Built-in Constants System.Drawing.Color.Black Sy
stem.Drawing.Color.Red System.Drawing.Color.Lime S
ystem.Drawing.Color.Yellow System.Drawing.Color.Bl
ue System.Drawing.Color.Magenta System.Drawing.Col
or.Cyan System.Drawing.Color.White
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Usage
Form1.ActiveForm.BackColor System.Drawing.Color.
Red _____________________________________________
____ Me.BackColor System.Drawing.Color.Red
________________________________________________
_
Refers to the current, active form