HP 35s HP 35s scientific calculator - User Guide - Page 224

If you replace lines S002 and S003 by SF0 and SF1, then flags 0 and 1 are set so lines S006 and S010 take the natural logarithms of the X- and Y-inputs. Use above program to see how to use flags Keys: (In RPN mode) S    Display: Description:  value  value   Executes label S; prompts for X value Stores 1 in X; prompts Y value Stores 1 in X ;displays X value after flag test Displays Y value after flag test You can try other three cases. Remember to press and to clear flag 1 and 0 after you try them. Example: Controlling the Fraction Display. The following program lets you exercise the calculator's fraction-display capability. The program prompts for and uses your inputs for a fractional number and a denominator (the /c value). The program also contains examples of how the three fraction-display flags (7, 8, and 9) and the "message-display" flag (10) are used. Messages in this program are listed as MESSAGE and are entered as equations: 1. Set Equation-entry mode by pressing  (the EQN annunciator turns on). 2. Press  letter for each alpha character in the message; press  for each space character. 3. Press  to insert the message in the current program line and end Equation-entry mode. 14-14 Programming Techniques