HP 35s HP 35s scientific calculator - User Guide - Page 195

Using INPUT for Entering Data The INPUT instruction (   Variable ) stops a running program and displays a prompt for the given variable. This display includes the existing value for the variable, such as where "R" is the variable's name, "?" is the prompt for information, and 0.0000 is the current value stored in the variable. Press  (run/stop) to resume the program. The value you keyed in then writes over the contents of the X-register and is stored in the given variable. If you have not changed the displayed value, then that value is retained in the X-register. The area-of-a-circle program with an INPUT instruction looks like this: RPN mode ALG mode To use the INPUT function in a program: 1. Decide which data values you will need, and assign them names. (In the area-of-a-circle example, the only input needed is the radius, which we can assign to R.) Simple Programming 13-13