Computer Programming Concepts and Visual Basic David I. Schneider

8.1 USER-DEFINED DATA TYPES
Records provide a convenient way of packaging as a single unit several related variables of different
types. Before we can explore this powerful variable type, we must first explore a new
category of variable, the fixed-length string.
■ FIXED-LENGTH STRINGS
Fixed-length string variables are named following the same rules as other variable types.
They are declared by statements of the form
Dim var As String * n
where n is a positive integer. After such a declaration, the value of var will always be a string
of length n. Suppose info is an ordinary string and a statement of the form
var = info
is executed. If info has more than n characters, then only the first n characters will be assigned
to var. If info has less than n characters, then spaces will be added to the end of the string to
guarantee that var has length n.
EXAMPLE 1
The following program uses fixed-length strings. In the output, San Francisco is truncated to a string of
length 9 and Detroit is padded on the right with two blank spaces.
Private Sub cmdGo_Click()
Dim city As String * 9
‘Illustrate fixed-length strings
picOutput.Cls
picOutput.Print “123456789”
city = ”San Francisco”
picOutput.Print city
city = “Detroit”
picOutput.Print city; “MI”
picOutput.Print Len(city)
End Sub
[Set picOutput’s Font property to Courier. Run, and click the command button.]
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