Computer Programming Concepts and Visual Basic David I. Schneider

454 Computer Programming Concepts and Visual Basic
#n, 0 specifies infinite width, that is, a carriage return/line feed pair will be sent to the printer
only when requested by Print # or Write #.
WITH/END WITH A multistatement block begun by With recName or With objName and
ended by End With is used to assign values to the fields of the named record variable or to
properties of the named object. The statements inside the block have the form .fieldName =
fieldValue or .propertyName = propertyValue. When you use this block, you only have to
refer to the record variable or object once instead of referring to it with each assignment.
WITHEVENTS If a class has events attached to it, and form code intends to make use of
these events, then the keyword WithEvents should be inserted into the statement declaring an
instance of the class. A typical declaration statement is Private WithEvents objectVariable As
className.
WORDWRAP The WordWrap property of a label with AutoSize property set to True determines
whether or not long captions will wrap. (When a label’s AutoSize property is False,
word wrap always occurs, but the additional lines will not be visible if the label is not tall
enough.) Assume a label’s AutoSize property is True. If its WordWrap property is set to True,
long captions will wrap to multiple lines; if its WordWrap property is False (the default), the
caption will always occupy a single line. If a label has its WordWrap and AutoSize properties
set to True, the label’s horizontal length is determined by the length of its longest word,
with long captions being accommodated by having the label expand vertically so that word
wrap can spread the caption over several lines. If a label’s WordWrap property is set to False
while its AutoSize property is True, the label will be one line high and will expand or shrink
horizontally to exactly accommodate its caption.
WRITE # After a sequential file is opened for output or append with reference number n, the
statement Write #n, exp1, exp2, . . . records the values of the expressions one after the other
into the file. Strings appear surrounded by quotation marks, numbers do not have leading or
trailing spaces, all commas in the expressions are recorded, and the characters for carriage
return and line feed are placed following the data.
XOR (Logical Operator) The logical expression condition1 Xor condition2 is true if condition1
is true or condition2 is true, but not if both are true. For example, (3“a”) is false because both 3“a”are true, and (“apple”>“ape”) Xor
(“earth”>“moon”) is true because “apple”>“ape”is true and “earth”>“moon”is false.
XOR (Bitwise Operator) The expression byte1 Xor byte2 is evaluated by expressing each
byte as an 8-tuple binary number and then Xoring together corresponding digits, where 1 Xor
0 and 0 Xor 1 both equal 1, while 1 Xor 1 and 0 Xor 0 both equal 0. For example, the expression
37 Xor 157 translated to binary 8-tuples becomes 00100101 Xor 10011101. Xoring
together corresponding digits gives the binary 8-tuple 10111000 or decimal 184. Thus, 37
Xor 157 is 184.
YEAR The function Year extracts the year from a serial date. If d is any valid serial date, then
the value of Year(d) is a whole number from 100 to 9999 giving the year recorded as part of
the date and time stored in d. [date]
SUPPORTING TOPICS
[BINARY FILE]: A file that has been opened with a statement of the form Open “filespec”For
Binary As #n is regarded simply as a sequence of characters occupying positions 1,
2, 3, . . . . At any time, a specific location in the file is designated as the “current position.”
The Seek statement can be used to set the current position. Collections of consecutive characters
are written to and read from the file beginning at the current position with Put and Get
statements, respectively. After a Put or Get statement is executed, the position following the
last position accessed becomes the new current position.