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2.5.5 Debug.Print Statement
One technique for debugging a program is called print statement debugging. The idea is that to
determine how your program is executing you insert statements into the program that display the values
of important variables or simply display a distinctive message so that you know what the program is
doing. Debug.Print is a special statement intended just for this purpose. The syntax is:
Debug.Print [<string-list>][;]
The <string-list> element represents zero or more string expressions separated from one another
by a semicolon. Each of the string expressions is evaluated in turn, from left to right, and the string result
of each is output to Com1. If the optional trailing semicolon is omitted, a carriage return/line feed will also
be output so that the next time something is output to Com1 it will appear on a new line. If you dont want
the subsequent output to be on a new line, simply add the semicolon at the end of the list. This is often
done when you need to compute several different values to output. You can use a separate
Debug.Print statement for each value and keep them all on the same output line by ending all but the
last with a semicolon. It is permitted, syntactically, to specify an empty string list but still include the
trailing semicolon. However, this construction does nothing.
Note that each of the items to be displayed must be a string. You can use the CStr() function to
produce a string from any value.
Examples
Dim i as Integer
Dim s as String
Debug.Print CStr(i)
Debug.Print "i = ";CStr(i)
Debug.Print "s = ";
Debug.Print s
Debug.Print
The last example, with an empty <string-list> and no trailing semicolon, will simply send a carriage-
return/linefeed to Com1.
The unusual form of Debug.Print is due to its heritage from Visual Basic. It should probably be called the
Print method of the system Debug object but it even departs from the traditional syntax of the methods
that are part of object-oriented languages. Nonetheless, it is included for compatibility as well as its utility.
2.5.6 Do-Loop Statement and Variants
This compound statement, briefly mentioned earlier in this document, is the basic repetition construct in
ZBasic. The syntax is:
Do
[<statements>]
Loop
This construct causes the sequence of zero or more statements to be repeatedly executed. However,
execution of the loop may be terminated using an Exit Do statement at which point control will transfer
to the first statement following the Loop statement. Note that the Do-Loop compound statement may be
nested and the Exit Do only terminates the innermost Do-Loop that contains it.