HP 33s Flags, 13–8, Example:, Meanings of Flags, 13–8 Programming Techniques, Displays the calculated value of, ! ª ! ! - % !  ! ) ! º<¸@

Example:

The "Normal and Inverse–Normal Distributions" program in chapter 16 uses the x<y? conditional in routine T:

Program Lines:	Description
(In RPN mode)

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! ª ! !- % !  ! ) ! º<¸@

! ! !

!  % ! #$ %

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Calculates the correction for X guess.Adds the correction to yield a new X guess.Tests to see if the correction is significant.

Goes back to start of loop if correction is significant. Continues if correction is not significant.

Displays the calculated value of X.

Line T0009 calculates the correction for Xguess. Line T0013 compares the absolute value of the calculated correction with 0.0001. If the value is less than 0.0001 ("Do If True"), the program executes line T0014; if the value is equal to or greater than 0.0001, the program skips to line T0015.

Flags

Aflag is an indicator of status. It is either set (true) or clear (false). Testing a flag is another conditional test that follows the "Do if true" rule: program execution proceeds directly if the tested flag is set, and skips one line if the flag is clear.

Meanings of Flags

The HP 33s has 12 flags, numbered 0 through 11. All flags can be set, cleared, and tested from the keyboard or by a program instruction. The default state of all 12 flags is clear. The three–key memory clearing operation described in appendix B clears all flags. Flags are not affected by {c{} {&}.

13–8Programming Techniques