Spreadsheet Programs
A computer spreadsheet is an automated ledger book. The spreadsheet—a large piece of paper with columns and rows that shows details about transactions--predates computers by hundreds of years. Computerized technology has provided the electronic replacement of the accountant's columnar pad, pencil, and calculator. Spreadsheet programs use columns and rows to display both numbers and text, and allow calculations to be performed on the numerical data. In addition to number-crunching, spreadsheet programs allow editing of data, graphical representation of data and financial modeling.
The development of the electronic spreadsheet began in 1961 with Richard Mattessich. Practically, the electronic spreadsheet originated with VisiCalc, the first such program, which was developed in 1978 by Daniel Bricklin, and refined with the assistance of Robert Frankston. Frankston's accomplishment was to package the program such that it occupied relatively little machine memory. This allowed VisiCalc to run on a personal computer, which proved very popular. In the jargon of the computer user VisiCalc is now recognized as the first "killer application" for personal computers. The program was discontinued in 1985.
In 1980, the dif format was introduced. This allowed spreadsheet data to be shared or imported into other programs, including text-based word processing programs. Three years later, Lotus 1-2-3, which was based on Visicalc, was developed by Lotus co-founder Mitch Kapor. Lotus 1-2-3 introduced naming cells, cell ranges and spreadsheet macros. It became the premier spreadsheet program for many years following its release. Towards the end of the 1980s, Microsoft and Corel released the spreadsheet programs Excel and Quattro pro, respectively. These emphasized the graphical user interface technology, with pull down menus and a point and click capability using a mouse-pointing device. Currently, Excel commands the biggest market share, although many other vendors have spreadsheet programs as well.
The columns and rows of a spreadsheet make up a grid pattern on each page (a page can also be called a worksheet). A number identifies each row, and a letter identifies each column. The intersection of a particular row and column is called a cell. Each cell is identified by its column and row number. The number of cells can be huge. Lotus 1-2-3 contains 8192 rows and 256 columns, which translates to over two million cells, and the latest version of Excel has 255 pages containing more than four million cells. Once the cells have been defined and the formulas for linking them together have been written, data can be entered in the cells. Each cell can contain a label, which is a text entry, or a value, which can be a number, formula or a formula's result. The active cell is indicated by the cursor. A new active cell can be selected, or the cursor can be used to drag the data from one cell to another cell.
Cells are linked mathematically by formulas. For example, D1 = B1 + F4 would display the sum of B1 and F4 in D1. The sum of data in designated cells in rows or columns can be programmed. Mathematical short cuts are also possible, with statistical designations such as SUM, AVERAGE, MEAN, MIN, and MAX being invoked for the assigned cells. These and other tools (copying, calculating a numerical difference between two cells) allow the spreadsheet data to be rapidly manipulated and analyzed. Selected values can be modified to explore how other values will change, and are called what-if scenarios.
Most spreadsheets are described as being multidimensional; one spreadsheet can be linked to another. A three-dimensional spreadsheet can be thought of as a stack of spreadsheets, connected mathematically to one another via formulas. A change made in one spreadsheet will automatically affect the other spreadsheets. Tax preparation software is one such example.
Another useful tool is the ability to represent numerical data in graphical form. For the Excel programming, this tool is called the Chart Wizard. Bar graphs, line graphs, column graphs, pie charts, area plots, and scatter plots can be constructed in two or three dimensions. This aids in perceiving trends or patterns that would otherwise be difficult to discern from a chart of numerical data, and the graphical representation of data is always appreciated by an audience in a presentation.
The educational value of electronic spreadsheets has been enormous. They have been most valuable for completing repeating tasks and for exploring the effects of different arrangements of data.
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