Computer Programming Concepts and Visual Basic David I. Schneider

"Hawaii", 1184000, 6471
"Alaska", 607000, 591000
Private Sub cmdDisplay_Click()
Dim state As String, pop As Single, area As Single
Dim s As String, p As Single, a As Single
'Calculate the population densities of states
picDensity.Cls Open "DEMOGRAP.TXT" For Input As #1
Input #1, state, pop, area
Call CalculateDensity(state, pop, area)
Input #1, s, p, a
Call CalculateDensity(s, p, a)
Close #1
End Sub
Private Sub CalculateDensity(state As String, pop As Single, area As Single)
Dim rawDensity As Single, density As Single
'The density (number of people per square mile)
'will be rounded to a whole number
rawDensity = pop / area density = Round(rawDensity)
picDensity.Print "The density of "; state; " is "; density;
picDensity.Print "people per square mile."
End Sub
[Run, and then click the command button. The following is displayed in the picture box.]
The density of Hawaii is 183 people per square mile.
The density of Alaska is 1 people per square mile.
FIGURE 3-2 Passing Arguments to Parameters in Example 6
Arguments and parameters also can be used to pass values from Sub procedures back to
event procedures or other Sub procedures. This important property is explored in detail in the
next section.
COMMENTS
1. In this text, Sub procedure names begin with uppercase letters in order to distinguish
them from variable names. Like variable names, however, they can be
written with any combination of upper- and lowercase letters. To improve readability,
the Visual Basic editor will automatically ensure that the capitalization
of a Sub procedure name is consistent throughout a program. For instance, if
you type Private Sub PROCEDURENAME and also type Call ProcedureName,
the second name will be changed to match the first. Note: Parameters appearing
in a Sub statement are not part of the Sub procedure name.
Sub Procedures, Part I 79