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.

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