1. GCSE Computing:: Selection (IF statements)

2. Data Types: Why we need them
Data types are needed just as in databases so our program knows how to handle our variables;
Getting the datatype right in first place is essential to reduce the amount of time finding errors (debugging) in your code;
In Visual Basic 6.0 we can use the following datatypes:
String (for storing letters, numbers and letters or words – e.g. “A4”, “September”, “N”)
Integer (for storing small whole numbers between and – e.g. 1, 1000, 11000)
Long (for storing large whole numbers between and )
Single (for small decimal numbers – e.g. 3.6 or 10.34)
Double (for large decimal numbers – e,g, )
Date / Time (can be setup in different formats e.g. DDMMYY or DDMMYYYY)
Boolean (holds only values of TRUE or FALSE – good for flags)
Currency (similar to the Single datatype)

3. IF Statements: Why we need them
If statements allow us to ask the computer or user questions. Based on the answer of these questions we can take a particular route;
Computers are only able to answer questions based on a 0 or 1, true or false, yes or no;
If statements take the form of the following:
Standard IF statements;
IF, Else statements;
IF, ElseIF statements;
Nested IF statements.

4. IF Statements: In practice
The following code shows how we can use common IF statements:
Dim sResponse as string
sAnswer = Inputbox(“Does the plant have chlorophyll?”)
If sAnswer = “No” then
msgbox “This is not fungi”
end if
if sAnswer = “yes” then
msgbox “This is fungi”
End if

5. IF Statements: In practice
The following code shows how we can use IF Else statements:
Dim sResponse as string
sAnswer = Inputbox(“Does the plant have chlorophyll?”)
If sAnswer = “No” then
msgbox “This is not fungi”
else
msgbox “This is fungi”
End if

6. IF Statements: In practice
The following code shows how we can use IF ElseIF statements:
Dim sResponse as string
sAnswer = Inputbox(“Does the plant have chlorophyll?”)
If sAnswer = “No” then
msgbox “This is not fungi”
ElseIF sAnswer = “Yes” then
msgbox “This is fungi”
End if