OpenOffice.org BASIC Guide - OpenOffice.org wiki

3
C H A P T E R 3
3 Runtime Library
The following sections present the central functions of the runtime library:
Conversion Functions
Strings
Date and Time
Files and Directories
Message and Input Boxes
Other Functions
Conversion Functions
In many situations, circumstances arise in which a variable of one type has to be changed into a variable of
another type.
Implicit and Explicit Type Conversions
The easiest way to change a variable from one type to another is to use an assignment.
Dim A As String
Dim B As Integer
B = 101
A = B
In this example, variable A is a string, and variable B is an integer. OpenOffice.org Basic ensures that variable B is
converted to a string during assignment to variable A. This conversion is much more elaborate than it appears: the
integer B remains in the working memory in the form of a two-byte long number. A, on the other hand, is a string,
and the computer saves a one- or two-byte long value for each character (each number). Therefore, before
copying the content from B to A, B has to be converted into A's internal format.
Unlike most other programming languages, Basic performs type conversion automatically. However, this may
have fatal consequences. Upon closer inspection, the following code sequence
Dim A As String
Dim B As Integer
Dim C As Integer
B = 1
C = 1
A = B + C
which at first glance seems straightforward, ultimately proves to be something of a trap. The Basic interpreter first
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