If you're an opera fan, you know how exciting a good opera can be, especially a classic work presented with the original foreign language libretto. If you're not an opera fan, you know how irritating it can be to listen to several hours of a foreign language libretto. With the advent of "supra titles" conveying the English-language interpretation of the content, those who until now have gotten little joy out of the opera experience will still find it repulsive, only this time in their native tongue. But at least now they will know why they don't enjoy the story.
That's really what comments do: tell you in your own language what is actually going on in a foreign language. In this book, the foreign language is Visual Basic, and English is the vernacular. You may find a particular block of Visual Basic code to be poorly written or even detestable, but if the accompanying comments are accurate, you can be disgusted in your own language, with a human language understanding of the process.
Comments normally appear on lines by themselves, but you may also attach a comment to the end of an existing code line. If a logical line is broken into multiple physical lines using the "_" line continuation character, a trailing comment is only valid at the end of the final physical line.
' ----- This is a standalone comment, on a line by itself. Dim counter As Integer ' This is a trailing comment. MsgBox("The counter starts at " & _ ' INVALID COMMENT HERE! counter) ' But this one is valid.
Comments begin with the comment character, the standard single quote character ('). Any text following the comment character is a comment, and is ignored when your code is compiled into a usable application. Any single quote that appears within a literal string is not used as a comment marker.
MsgBox("No 'comments' in this text.")
Comments can also begin with the "REM" keyword (as in "REMark"), but most programmers use the single-quote variation instead.