Reference Guide
3-32 Full Command and Function Reference
CASCMD
Type: Command
Description: Displays a list of CAS operations. Selecting one with OK displays a description, related
operations, an example of the operation, and the option to copy the example to the command
line. More details are given in Appendix C and Appendix H of the User’s Guide. If level 1 of the
stack contains a string, the list of CAS operations will be displayed beginning at this point.
Access: Catalog, …µ
,
or tools IL
See also: HELP
CASE
Type: Command
Description: CASE Conditional Structure Command: Starts CASE … END conditional structure.
The CASE … END structure executes a series of cases (tests). The first test that returns a true
result causes execution of the corresponding true-clause, ending the CASE … END structure. A
default clause can also be included: this clause executes if all tests evaluate to false. The CASE
command is available in RPN programming only. You cannot use it in algebraic programming.
The CASE … END structure has this syntax:
CASE
test-clause
1
THEN true-clause
1
END
test-clause
2
THEN true-clause
2
END
.
.
test-clause
n
THEN true-clause
n
END
default-clause (optional)
END
When CASE executes, test-clause
1
is evaluated. If the test is true, true-clause
1
executes, then
execution skips to END. If test-clause
1
is false, test-clause
2
executes. Execution within the CASE
structure continues until a true clause is executed, or until all the test clauses evaluate to false. If
the default clause is included, it executes if all test clauses evaluate to false.
Access: !°
BRCH CASE
( °is the left-shift of the Nkey).
Input/Output:
Level 1/Argument 1 Level 1/Item 1
CASE
→
THEN
T/F
→
END
→
END
→
Example: The following program takes a numeric argument from the stack:
•
if the argument is negative, it is added to itself
•
if the argument is positive, it is negated
•
if the argument is zero, the program aborts
« → X « CASE
'X>0' THEN X NEG END
'X<0' THEN X DUP + END
'X==0' THEN 0 DOERR END
END » »
See also: END, IF, IFERR, THEN