And now for something completely different! Different, that is, from your typical Casio calculator. The fx-4500P prominently displays the words, "DOT MATRIX LCD", on top, but don't let it mislead you: this is not a graphing calculator. What it is is a fairly decent, high-end scientific programmable. With an over 1000-step program memory, and a comprehensive set of program instructions, it is a pleasant multifunction machine.

The programming model of the fx-4500P is somewhat idiosyncratic. Programs are stored in "files", which you select by name or number when you get into program entry mode. Each file has numbered lines. To execute a program, you use the Prog instruction, followed by the name of the file; a number will not suffice. In a program, assignment instructions are BASIC style: variable name, equation sign, followed by the expression. This differs from the way assignment instructions are implemented on Casio's graphing calculators.

Idiosyncratic, however, doesn't mean bad. About the only real complaint I have is this machine's cramped keyboard: three shift keys are used to invoke a variety of essential, but often cryptic, key combinations.

The programming model of the fx-4500P is demonstrated by the following example, which computes the logarithm of the Gamma function using the Lanczos approximation to a very high degree of accuracy:

F1 L1	X=Ans
F1 L2	Z=Abs X
F1 L3	G=2.506628275+6.3E-10+(225.5255846+1.9E-8)/Z-
	(268.2959738+4.1E-8)/(Z+1)+(80.90308069+3.5E-9)/(Z+2)-
	(5.007578639+7.1E-10)/(Z+3)
F1 L4	G=ln (G+1.146848954E-2+5.4E-12)/(Z+4))+(Z-.5)ln (Z+4.65)-Z-4.65
F1 L5	X>0⇒Goto 1.
F1 L6	G=ln (-π/Z/sin πZ)-G
F1 L7	Lbl 1
F1 L8	G