Atari 400 Basic Reference Manual page 48

40 Strings
String Comparisons and Sorts
In string comparisons, the logical operators are used exactly the way they are
with numbers. The second program in Appendix His a simple example of bub-
ble sort.
In using logical operators, remember that each letter, number, and symbol is
assigned an ATASCII code number. A few general rules apply to these codes:
1.
AT ASCII codes for numbers are sized in order of the numbers' real
values and are always lower than the codes for letters (see Appendix C).
2. Upper case letters have lower numerical values than the lower case let-
ters. To obtain the AT ASCII code for a lower case letter if you know the
upper case value, add 32 to the upper case code.
Note:
Atari BASIC's memory management system moves strings around in
memory to make room for new statements. This causes the string address to
vary if a program is modified or Direct mode is used.