This spreadsheet emulator attempts to demonstrate the basic characteristics of spreadsheets such as found in commercial applications. Primary among these characteristics are the two "views" of the spreadsheet - the view that shows the actual contents of the cells and the view that displays the values associated with those contents. These are termed the "edit mode" view and the "display mode" view respectively.

In the edit mode the user may enter items into the individual cells. Cells may contain:

• numeric representations (integers or real numbers),
• strings (alphanumeric objects in which the leftmost character is alphabetic), or
• formulae (in which the leftmost character is =).

Formulae are represented as arithmetic expressions in terms of the computed values contained in other cells that are referenced by cell names composed of the column letter and row number shown in the spreadsheet. Expressions may include the arithmetic operations of addition (+), subtraction (-), multiplication (*), division (/), modulus (%), equality (==) or not equal (!=).

Cell names in formulae may be entered in either upper or lower case; they will be automatically changed to upper case. Similarly strings will always be converted to all upper case.

Several mathematical functions are provided:

 ABS Absolute value of argument CEIL Ceiling, integer value greater than argument FLOOR Floor, integer value less than argument MAX Maximum of two arguments MIN Minimum of two arguments RANDOM Random number between 0 and 1 ROUND Rounded value of argument SIN Sine function of argument (in radians) TAN Tangent function of argument (in radians) SQRT Square Root of argument

Two special functions are available: SUM(<range>) and AVERAGE(<range>) where range is the range of cell names over which the SUM or AVERAGE is to be computed; the range is specified in the form <cellname>:<cellname>. The range of cells must be in a single row or column and specified so that the first cellname is less than the last cellname in the range. SUM and AVERAGE cannot be included in a larger expression; that is, they can be only used as the complete formula in a cell.

Once the entries have been edited into the spreadsheet in the "edit mode", the values associated with each cell may be evaluated by changing to the 'display mode" through the "CHANGE MODE" button. In this mode the formulae in the cells will be evaluated and the result displayed. Where the formula is a simple copy, such as =F3, then no evaluation will be performed and the value associated with the cell is simply copied to the new location. If the displayed result is "NaN", then the evaluation process resulted in a non-representable value, usually resulting from attempting to use a string in an arithmetic operation.

If the user attempts to edit a call while in the DISPLAY mode, the mode is automatically changed to EDIT.

Last updated 2002/04/05