The apostrophe allows explanatory comments, or remarks, to be inserted in a program. These may be included anywhere in the source code and extend to the end of the line. Comments are ignored when the program is run.
- REM can also be used to insert comments but may only be used as the last, or only, statement on a line.
- QBasic metacommands like $INCLUDE must be included in a comment using either REM or '.
- Apostrophe comments, unavailable in earlier dialects of the BASIC language, are now generally favored over REM statements for their greater flexibility.
- Comments are also useful for disabling code for program testing and debugging purposes.
COLOR 11: PRINT "Print this...." ' PRINT "Don't print this program comment!"