Programming continued

1
Programming (continued)

• Chapters 3.2 and 3.3

2
Review

• Whats the difference between VB and other
  programming languages?
• What is Pseudocode?
• When your writing code where will you spend the
  most time?
• At what point do you start writing code in VB?

3
Review

• What is a reserved word?
• What are properties? (examples)
• If you get errors what should you do?

4
What we did last time?

• Create a Form with 4 buttons labeled, Red, Blue,
  White, and Yellow. Each one will change the
  color of the background or foreground of a textbox

5
Math is Fun

• Standard math operations
• Addition
• 55
• Subtraction -
• Division /
• Multiplication
• Exponentiation
• 52 52

6
What more fun that Math

• Incrementing Numbers
• counter counter 1
• counter 1
• Decrementing Numbers
• counter counter -1
• counter - 1

7
More Math

• Square Root
• Math.Sqrt(9) 3
• Rounding
• Math.Round(number, precision)
• Math.Round(2.1234) 2.0
• Math.Round(2.182,1) 2.2
• Modulo
• 5 Mod 3 ??
• 21 Mod 2 ??

8
More Math

• Square Root
• Math.Sqrt(9) 3
• Rounding
• Math.Round(number, precision)
• Math.Round(2.1234) 2.0
• Math.Round(2.182,1) 2.2
• Modulo
• 5 Mod 3 2
• 21 Mod 2 1

9
Examples

• a(bc)
• abc
• (bca)/a2
• b(b-2)ac
• Let a 2 b4 c2

10
Variables

• Variables are buckets that hold data
• Algebrax 5y 2xx and y are variables that
  can change
• Visual Basicdim x As Integerdim y As Integerx
  5y 2 xtextBox.Text y
• Valid Names (all rules in book)

11
Variable Types

• So we have buckets of data types allow us to tell
  what the data is like
• Variable x is an Integer
• What types
• Integer
• Double
• String
• Date
• VariantType

12
Defining Variables

• In VB you need to define your variables
• Dim varname as lttypegt
• Dim x as Integer
• Dim name as String
• Dim bday as Date
• Im declaring x as an integer.
• Dim var1, var2, var3 as Integer

13
Strings

• What is a string?
• Your name. Your Street.
• Strings are represented with quotes
• This is a string
• Dim s as Strings Foo Blats Grrrreat!

14
String Operations

• Concatenation
• Dim resp, auth as Stringresp Respect my
  auth authority!txtOutput.Text resp
  auth
• Once ran the output will sayRespect my
  authority!

15
Math with Strings?

• Need to convert String to Integers or Doubles
• CDbl(ltstringgt)
• CInt(ltstringgt)
• Dim sum, count as Integer
• Dim avg as Double
• sum CInt(sum.Text)
• count CInt(count.Text)
• avg sum / count

16
More String Stuff

• str.Length
• The number of characters
• str.ToUpper
• foo Blat.ToUpper FOO BLAT
• str.ToLower
• Str.Trim
• the text is here the text is here

17
Strings, Strings, Strings

• str.Substring(m,n)
• Visual.Substring(0,2) Vi
• Visual.Substring(3,2) ua
• 412.327.1234.Substring(5,3) 327
• str.IndexOf(str2)
• fanatic.IndexOf(a) 1
• fanatic.IndexOf(ati) 3
• fanatic.IndexOf(z) -1

18
Just a bit more on Strings

• The Empty String
• empty_str
• empty_str.clear()
• Initial Value
• Dim today as String Monday
• Multiple Line (continuation)
• msgInvention is the _mother of necessity.

19
Code Comments

• These are notes put in your code
• Dim x, y as Integer
• Dim avg as Double
• the average is sum over total - bryan
• avg x / y
• Note These are very important if you want to get
  full credit on your projects.

20
The good and the bad

• The With StatementWith lstElem.Items
  .Clear() .Add(foo) .Add(blat)
  .Add(bar)End With

21
Lets play

• Create an application that has two inputs and a
  button to compute the sum of the two numbers.

22
Another Example

• Write a program to request the team name, accept
  the number of wins and number of loses then
  display the followingltteam namegt won . of
  the time