Constants and
variables
VFCalc provides the ability to
define constants and variables to be used in formulas.
A constant receives value at the
time of its creation, this value is fixe and can not be changed by calculations.
A variable receives a value at the
time of its creation, but this value is not fixed, it can change by saving the
result of a calculation or by entering a value from the keyboard during the
execution of a calculation.
To save the calculated result of a
formula in a variable, simply insert the symbol of the variable before or after
the equal sign (=).
Example :
3X4+6=variable
or
variable=5+6X10
During execution of the calculation,
VFCalc present the variables in the formula to the user for confirmation
of the value of the variables or for introduce a new value in the
variables.
All constants and variables are
stored in a list of constant or variable. To access the list of constants, use « C »
on the keyboard, for variables, use « V ». The lists are organized
with folders and subfolders.
To create a
constant, a variable or a folder, use the « + » button at the bottom
right. For a folder,
you are asked for a name. For a constant or a variable, you are asked for a
name, a symbol, a value, and a description (optional). The value is preset with
the result of the last calculation but you can change it. The symbol is used to
represent the constant or variable in the formulas, a keyboard with the Greek
alphabet is available. You can also create a constant or a variable directly
from the keyboard of the calculator, use « C+ » or « V+ »
(2ndF).
To view or edit an item, press the « Edit »
button at the top right, select the item (only one) to view or edit and press
the « Details » button. You have direct access to the details of a
constant or a variable by pressing the detail icon (blue circle) on the right.
To delete an item or items, press
the « Edit » button, select the item or items and press the
« Delete » button.
To move an item or items, press the « Edit »
button, select items and press the « Move » button. A new window asks
you to select the folder where to move the selected items.
After viewing or changes are
complete, press the « Done » button in the upper right.
To use a constant or a variable,
just press on it in the list and its symbol will be introduced in the
calculator (display).
VFCalc has, by default, two
constants (pi and e) and a variable (M). They are directly accessible from the
keyboard and can not be changed except for the value
of M.
The value of M is always displayed
next to the left triangle.
VFCalc also has
several examples of constants and variables. These constants and variables are
used in examples of formulas.