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>a2:"                     LESSON2 -- Entering Data
>a4:"       In this lesson we will practice entering data in the Stock
>a5:" Portfolio spreadsheet,  (filename 'b:stockex.pc'), which we use in 
>a6:" Lesson 1.  This spreadsheet already contains some data--
>a7:" labels, numbers, and formulas--but let us practice adding more, 
>a8:" beginning with numbers.
>a9:"    Let us begin by splitting the screen and calling up the 'stockex.pc'
>a10:" file. Move the cursor to line 11 (the indicator in the lower right edge
>a11:" of the screen should read 'a11' when you're there) and enter the 
>a12:" CREATE TWO WINDOWS Command:
>a13:"                           Control--x   2
>a14:"     ÆAnswer 'n' for "no", to the prompt "Sychronize windows?"Å
>a15:" Next move the cursor into the other ÆtopÅ window using:
>a16:"                         Control--x  o (the letter 'o')
>a17:"     Use the 'Other Window' commands learned in the first lesson to
>a18:" scroll the bottom window:
>a19:"           FORWARD:    Control--x  Control--v
>a20:"           BACKWARD:   Control--x  Control--z
>a21:"     Call up the 'stockex.pc' file.  Enter the FIND FILE Command:
>a22:"                   Control--x  Control--f
>a23:"   When Perfect Calc responds, "File to Find <CR>: " enter the filename:
>a24:" 'b:stockex.pc', followed by a carriage return.  
>a26:"  NUMBERS
>a27:"       Perfect Calc distinguishes a number from a label or a formula, by
>a28:" the first character that you type.  That is, if the first character is
>a29:" a ' - ' (hyphen, or minus sign), a ' . ' (period, or decimal point),
>a30:" or any digit, 0 - 9, Perfect Calc assumes you are entering a number.
>a32:"     Using an appropriate cursor command or arrow key, move the cursor
>a33:" to position 'c6' and type a value for the current price of Xerox stock,
>a34:" e.g. $40.  Type the number '40' (omitting the dollar sign) and hit
>a35:" 'Enter' or 'Return'. (Use the DELete key to erase typing errors.)
>a36:"       At the first digit Perfect Calc displays the message "Number:"
>a37:" in the Prompt Line.  The number you type appears initially following 
>a38:" this message.  It will not be entered into the spreadsheet until
>a39:" you type 'Enter' or 'Return'.
>a40:"       After you hit the 'Return' key, Perfect Calc enters the number
>a41:" and recalculates the spreadsheet, displaying a value of '8000' for 
>a42:" 'Current Value', position 'e6'.
>a43:"       Notice that numbers are displayed showing two decimal places,
>a44:" which is Perfect Calc's default display notation.  In Lesson 6 we
>a45:" will see how this can be changed.
>a47:"  FORMULAS
>a48:"       Formulas express the relationships that exist among the data
>a49:" held in your spreadsheet. For example, a formula for your home 
>a50:" 'expenses' might be: Expenses = Rent + Utilities + Food.  In general,
>a51:" formulas consist of numbers, variables, arithmetic operators, and/or 
>a52:" functions. Arithmetic operators are the common symbols of arithmetic
>a53:" that we are all familiar with:
>a55:"       ^          To the power of  (e.g. 3^2 means "3 to the power of 2",
>a56:"                                    or 'three squared' or 3 x 3 = 9)
>a57:"       *          Multiplication
>a58:"       /          Division
>a59:"       +          Addition
>a60:"       -          Subtraction
>a61:"       Move the cursor to position 'e6', which records the 'Current
>a62:" Value' of the Xerox stock.  The formula for this position, as displayed
>a63:" in the Prompt Line, instructs Perfect Calc to multiply ( * ) whatever
>a64:" value is contained in position 'b6' ('Number of Shares') by whatever
>a65:" value is held in position 'c6' ('Current Price').  This result is then
>a66:" displayed in position 'e6' ('Current Value').
>a67:"      As you can see, only the value which the formula computes displays
>a68:" on the spreadsheet, while the formula itself  ÆFormula: b6 * c6Å
>a69:" displays in the Prompt Line, and then ONLY when the cursor is occupying
>a70:" the entry position that contains it.
>a71:"       Let us enter a formula.  Move the cursor to position 'f6', which
>a72:" records 'Percentage Gain/Loss'.  This entry position will hold a 
>a73:" formula that will compute the percentage we have gained or lost on
>a74:" our investment in this stock.  The formula will be:
>a76:"                    f6 = (c6 - d6) / d6
>a78:"       This instructs Perfect Calc to subtract the Purchase Price from
>a79:" the Current Price, and to divide the result by the Purchase Price.  
>a80:" The result will be displayed in position 'f6'.
>a81:"       With the cursor at position 'f6' type an equals sign ( = ).
>a82:" This tells Perfect Calc that you wish to enter a formula for this
>a83:" position.  Start typing the formula now.  Again, it will be:
>a85:"               FORMULA:  f6= (c6 - d6) / d6
>a87:"       Blanks are ignored by Perfect Calc and so may be inserted
>a88:" for readability.  If you make a mistake, use the DELete Key to backup
>a89:" and retype.  As you did with numbers, type the formula at the prompt
>a90:" line and then enter it onto the spreadsheet with a carriage return.
>a91:"       Perfect Calc recalculates the spreadsheet displaying a result
>a92:" of '-0.20' in position 'f6', indicating that a loss of 20 percent has
>a93:" occurred for this stock.  Actually, percentages should be displayed
>a94:" as whole numbers, not as decimal fractions.  Let us change the formula
>a95:" so that it will do this.
>a96:"       Perfect Calc provides a very convenient method of changing
>a97:" a formula (or label) entry, which does not require retyping the entire
>a98:" entry. Called the EDIT ENTRY Command, it cause the formula which the
>a99:" cursor is occupying to be displayed in the Prompt Line, where you
>a100:" you may change it however you wish.  To help you, Perfect Calc 
>a101:" modifies several of its commands:
>a103:"       Control--a   Moves Cursor to BEGINNING of Prompt Line
>a104:"       Control--e   Moves cursor to END of Prompt Line
>a105:"       Control--f   Moves Cursor FORWARD one character
>a106:"       Control--b   Moves Cursor BACKWARD one character
>a107:"       Control--d   DELETES character occupied by the cursor
>a108:"       DEL Key      DELETES characters backward
>a109:"       Control--g   CANCELS changes made & returns to original formula
>a110:"       Return key   Enters the modified formula.
>a111:"     At this time, with the cursor on position 'f6' type the EDIT
>a112:" ENTRY Command:
>a113:"                         Control--x  e
>a114:"     Perfect Calc responds by displaying the formula in the Prompt Line:
>a115:"                     EDIT: (c6 - d6) / d6
>a116:"       Using the above editing commands, change the formula to read:
>a118:"              f6 = ((c6 - d6) / d6) * 100
>a119:"       When you have finished, enter the modified formula into the
>a120:" spreadsheet using a carriage return.  Perfect Calc automatically
>a121:" recalculates the spreadsheet, displaying a new value of '-20.00' in 
>a122:" entry position 'f6'.
>a124:"  FUNCTIONS
>a125:"       Now let us consider a formula containing a simple function.  A
>a126:" function is a kind of pre-structured formula which performs a
>a127:" mathematical operation, and which would be difficult or time consuming
>a128:" to structure ourselves.  Functions perform such operations as computing
>a129:" sums, averages, square root, and so forth.
>a130:"       Move the cursor to position 'e18', the entry which will compute
>a131:" 'Current Equity'.  This figure, which is the sum of all values in
>a132:" column 'e', will represent the total current worth of the stocks we
>a133:" own.  Presently, we have only one stock, Xerox, showing a total current
>a134:" value of $8000.  However, in a few moments we will be adding stock for
>a135:" other companies into lines 6 through 15.  We could write our formula
>a136:" as follows:
>a137:"            e18 = e6 + e7 + e8 + e9 + e10 + e11 + e12 + e13 + e14 + e15
>a138:"     This would give us the correct total.  However, it is an awkward 
>a139:" formula, and if we add more than 8 stocks, we will have to rewrite it.
>a140:"       Perfect Calc provides an answer with its 'sum' function, which 
>a141:" will compute the sum of variables over a 'range'.  A range is simply
>a142:" any continuous series of entry postions, whether in a line, a column,
>a143:" or a rectangular area of both lines and columns.  The entry positions
>a144:" 'e6' through 'e15' represent a columnar range of values.  Using the
>a145:" sum function we can write our formula very concisely, as follows:
>a146:"        e18 = sum(e6:e15)
>a147:"   Notice that the range is enclosed in parentheses and follows right
>a148:" after the function name, leaving no blank space.  As well, the range is
>a149:" specified by the first and last entry positions, separated by a colon.
>a151:" Enter this formula into entry position 'e18':
>a152:"                   FORMULA: e18=sum(e6:e15)
>a153:" Use the equal sign '=' to start the formula entry.  This entry recalcu-
>a154:" lates the spreadsheet displaying a value of $8000 for 'Current Equity'.
>a156:"     Perfect Calc provides a large number of built-in functions similar
>a157:" to the 'sum' function.  These include virtually all of the built-in
>a158:" functions found on other electronic spreadsheet programs.  However, as
>a159:" we will learn in lesson8, it is possible to build a 'user-extendable'
>a160:" functions library which makes the number of functions available 
>a161:" virtually limitless.  Let us examine the current built-in functions
>a162:" listed in the Help Menu:
>a163:"             Type Help:  ?   and select '5'.  
>a164:"    NOTE: To return to these instructions scroll the bottom window using:
>a165:"                 Control--x  Control--v
>a172:" LABELS
>a174:"       The last type of data entry we will examine are labels.  Labels
>a175:" are those words and symbols in the spreadsheet that identify the
>a176:" various lines, columns, and entry positions.  At present there are more
>a177:" labels on our spreadsheet than numbers and formulas.  Labels make
>a178:" the spreadsheet not only easy to use but also aesthetically pleasing
>a179:" to view.  No computations are performed on labels.
>a181:"       Any printable character which does not begin a command, a number
>a182:" or a formula may begin a label.  However, should it happen that a label
>a183:" must begin with, for example, a hyphen, an equals sign, or a period,
>a184:" which would otherwise signal a number or a formula, the label can be
>a185:" 'forced' by typing a double quote ( " ) before beginning the label.
>a187:"       Move the cursor to entry position 'a7' and type the label 'IBM'.
>a188:" As with numbers and formulas, the label is displayed initially in the
>a189:" Prompt Line following the message:  "LABEL:  ".  Instead of entering
>a190:" the label with the return key, use the FORWARD Command (Control--F).
>a192:"      Notice that Perfect Calc enters the label, and then moves the 
>a193:" cursor right one column position, where it is ready to receive a 
>a194:" numeric value for 'Number of Shares'.
>a196:"     Make up and enter sample numbers for IBM stock.  Each time a number
>a197:" is entered, Perfect Calc recalculates the spreadsheet. When you have
>a198:" finished with IBM, enter stock holdings for other companies, such as
>a199:" General Motors, Bank of America, Georgia Pacific, etc.
>a201:"       Once the data has been entered, change the 'Current Price' for
>a202:" various stock, observing how Perfect Calc automatically recalculates
>a203:" the current value of your stock holdings, your percentage gain or loss
>a204:" for each, and your current equity.
>a206:"       THIS is the power of Perfect Calc!
>a208:"       When you have finished, and if you wish to continue to the next
>a209:" lesson, which deals with storing and printing the spreadsheet, simply
>a210:" clear the entire memory and read in the 'lesson3.pc' file.
>a211:"     The CLEAR ENTIRE MEMORY Command is:  Control--x  Control--k
>a213:"     The FIND FILE Command is:  Control--x  Control--f
>a215:"       If you do not wish to continue with the lessons now, type the
>a216:" QUIT Command:
>a217:"                Control--x  Control--c
>a218:"     Answer 'y' for yes to Perfect Calc's question:  "Ignore changes
>a219:" this session?"
>a220:"                      END OF LESSON 2
>a1
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