In this chapter we examine three different applications, all concerned with using and managing data, that might be of interest to a hypothetical small business, the Huli Huli Pineapple and Papaya Company. These applications are
l Symbolic and numeric computation
Each application is possible because of advances that have taken place in computer hardware and software. Although we use a small business context to present these applications, they are equally useful, in various forms, for individuals and for multinational corporations.
An electronic spreadsheet combines elements of a calculator, a word processor, a database manager, a graphing tools, a modeling and forecasting tool, and an accountant’s ledger. The first spreadsheets software, VisiCalc, developed in 1979, was modeled after the traditional accountant’s ledgerbook or spreadsheet. But the advantages of an electronic spreadsheet soon became apparent, and this single software package was a principal motivator in the growth of microcomputer use. Today, spreadsheets are one of the most widely used software packages, and they continue to incorporate increasing capabilities. Spreadsheets are of value to individual homeowners and investors, business planners, scientists, economists, teachers, and anyone who has text and numeric information to organize, manipulate, or display.
An empty spreadsheet contains a two-dimensional grid of cells. The rows are labeled by numbers 1, 2, 3, …, and the columns are labeled by letters A through Z, then AA, AB, and so on. Giving a column letter and a row number identifies a particular cell in the grid. On some systems, cells, or blocks of cells, can also be named and referred to by name. The dimensions of the grid are defined by the software package but are usually in the range of thousands of rows and a few hundred columns. Only a portion of the grid, called a window, is visible at any one time on the screen. The user may scroll (move) the window through the grid to make different parts visible. The user can also adjust the width of any column in the grid.
Initially, the window is always located in the upper left corner of the grid, at the beginning of the letter-number cell identification system (cell A1). Figure 11.1 shows a window in an empty spreadsheet, with cell D2 shaded. The user generally selects a certain cell to be “active” by using a mouse, the tab key, or the arrow keys to move a cursor (marker) to the desired cell.
Three kinds of information can be stored in a spreadsheet cell. A cell can contain text information, also called a label, which appears on the screen in that cell. Text information is used at the top of a column to label the data appearing in that column, or at the left of a row to label data in that row. Text can also be used to label any single cell. Text information may be longer than the standard-sized cell, so the column size is frequently expanded to accommodate text information. The user can use formatting commands to direct how the text will be displayed, including whether it is to be centered or right- or left-justified within the cell; what the type font and size are to be; and whether certain words should be boldface or italic. In Figure 11.2, cells A1, B1, and C1 contain labels.
The second kind of information that a cell can contain is a numeric value. Numeric values also appear on the screen, and, as with text, the user can choose the format in which the number will be displayed.