Programming exercises in Java, VBA, VB.NET
March 24, 2009 @ 8:21 AM by JP • 1 views • No Comments »
Submitted for your approval: three programs that all do the same thing, in three different languages, as a programming exercise for those of you interested in this sort of thing.
Each of these three programs does the same thing, in nearly the same way: You choose whether you want upper or lower case letters, and the code builds a string consisting of the alphabet, either upper or lower case.
Java:
The Java program begins by creating a 26 character array, then gets the initial Chr() value from a custom function called getCase. This function prompts the user for the case they want for the alphabet. If you type 'lower', it returns the number 97 (the character value for the letter 'a') otherwise it returns 65 (the character value for the letter 'A').
(Tip: you can verify these values by opening Excel and, in cell A1, typing =CHAR(ROW()) and filling down to row 122 and beyond.)
Then a For loop loops through the numbers 0 through 25 (the elements of the alphabet[] array) and assigns characters to each member of the array. The current value of the alphabet array is printed to the console / debug window.
The character value is incremented with each iteration of the loop, so it either loops through the numbers 97 through 122 (lower case) or 65 through 90 (upper case), depending on what the user chose when prompted earlier. The char modifier casts the number into its character equivalent.
import java.util.*;
public class alphab
{
static Scanner console = new Scanner(System.in);
public static void main(String[] args)
{
char[] alphabet = new char[26];
int asc_val = getCase();
for (int i = 0; i < alphabet.length; i++) {
alphabet[i] = (char)asc_val;
System.out.print(alphabet[i] + " ");
asc_val++;
}
}
private static int getCase() {
// returns user choice to calling sub
// if no choice is made (or invalid choice), assume uppercase
// variables
String case_type = new String();
final String lwr = "lower";
int return_type = 65;
System.out.println("Enter 'upper' for uppercase,
'lower' for lowercase");
case_type = console.next();
if (case_type.equals(lwr))
return_type = 97;
return return_type;
}
}
VBA:
In VBA, we can't print the array members directly, so we build a string and display it in a messagebox. Otherwise it's nearly identical.
Dim alphabet(1 To 26) As String
Dim asc_val As Long
' get user choice, upper or lower
' default is upper
asc_val = getCase
' loop through array and populate it with alphabet
Dim i As Long
Dim strAlphabet As String
For i = 1 To 26
alphabet(i) = Chr(asc_val)
' build string consisting of upper or lowercase letters
strAlphabet = strAlphabet & " " & alphabet(i)
asc_val = asc_val + 1
Next i
' show result
MsgBox strAlphabet
End Sub
Private Function getCase() As Long
' returns user choice to calling sub
' default is upper case
Dim case_type As String
Dim return_type As Long
Const lwr As String = "lower"
Const UPPER_CASE As Long = 65 ' asc char value for uppercase A
Const LOWER_CASE As Long = 97 ' asc char value for lowercase a
case_type = InputBox("Enter 'upper' for uppercase, 'lower' for lowercase")
If case_type = "lower" Then
return_type = LOWER_CASE
Else
return_type = UPPER_CASE
End If
getCase = return_type
End Function
VB.NET:
The VB.NET version is most similar to the VBA version, with a few borrowed elements from Java.
Public Sub alphab()
Dim alphabet(0 To 25) As String
Dim asc_val As Long
asc_val = getCase()
' loop through array and populate it with alphabet
Dim i As Long
Dim strAlphabet As String
For i = 0 To 25
alphabet(i) = Chr(asc_val)
' build string consisting of upper or lowercase letters
strAlphabet = strAlphabet & " " & alphabet(i)
asc_val += 1
Next i
' show result
MsgBox(strAlphabet)
End Sub
Private Function getCase() As Long
' returns user choice to calling sub
' default is upper case
Dim case_type As String
Dim return_type As Long = 65
Const lwr As String = "lower"
Const LOWER_CASE As Long = 97 ' asc char value for lowercase a
case_type = InputBox("Enter 'upper' for uppercase, 'lower' for lowercase")
If case_type.Equals(lwr) Then
return_type = LOWER_CASE
End If
getCase = return_type
End Function
End Class
Notes: The .NET IDE (Visual Basic 2008 Express Edition) wouldn't let me create a one-based array. Or at least, I don't know how. If it's the same as VBA (putting Option Base at the top of the module) then I'd rather not.
It's funny to see how you can combine elements of VBA and Java in .NET. For example, you can declare and initialize a new variable at the same time in .NET (i.e. "Dim return_type As Long = 65"), saving space. VBA won't let you do that.
You can also use operators like += in .NET; VBA just throws an error.
Java is the only language of the three that can print multiple times to a single line, using the print function. With VBA and VB.NET, I had to build strings in order to get everything to print on one line; Debug.Print inserts a carriage return every time I use it.
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One suggestion with VBA. To display an array as a string, it's much more important to first populate the array, and THEN convert it to a string, like this:
strAlphabet = Join(alphabet," ")
The second argument of the Join determines what character, if any, will be used to separate the array values.
I used a loop and combined those two steps, but you've got a point. Built in functions (where available) should be used in place of loops whenever possible.