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1 PC-CALC by John L. Vandegrift and Guy C. Gordon 2 Preface Welcome to PC-Calc, the electronic spreadsheet designed for use with the IBM-PC or VICTOR 9000 personal computer. This user's manual will serve as your guide. The PC-Calc user's manual is intended to accommodate a large number of people with a wide range of computer exper- ience. It is organized into three main sections. Section l is an introduction to PC-Calc and includes information about starting PC-Calc and what the user will see. You should read this section before trying anything with the PC-Calc program. Section 2 is an instructional section, containing les- sons which have been structured to foresee some of problems and questions that will arise. These lessons will lead you from initiating a PC-Calc session through various exer- cises which illustrate how PC-Calc can assist in solving problems and increasing your efficiency. The exercises should be run with the terminal in front of you, as they are designed to lead you through the features of PC-Calc. With usage, you will become familiar with some of the more advanced features of PC-Calc. Section 3 is the command reference. This section con- tains a description of each of the commands available to the user. As you use the advanced features of PC-Calc, and become more familiar with them, you will find yourself spending more time in this section. The best way to learn PC-Calc is to use it. Do not be afraid of making mistakes and experimenting. No matter what you type at the keyboard, you cannot hurt the computer or the PC-Calc program, although it is always a good idea to have a backup of all programs. PC-Calc is laid out similarly to classic spreadsheet programs. It is not intended to completely replace these programs, but will allow you to learn what a spreadsheet is all about. Written in BASIC, PC-Calc has many limita- tions. First, interpretive Basic is slow. Second, it must pause once in a while to free more space for variables. (When this happens PC-Calc will not respond for up to 2 minutes.) If you are running the compiled version of PC-Calc these may not be problems. Third, Basic limits your space to about 1000 cells. If you start using PC-Calc and find that it serves a useful purpose in your home or at work, then it may be time to start looking at the full priced spreadsheets, which are bigger, faster, have more features, (and cost a whole lot more). Your experience with PC-Calc will be of great value to you in evaluating the many com- mercially available spreadsheets. 3 1. Overview Spreadsheet application programs, of which PC-Calc is one, were born out of the observation that many problems are commonly solved using a pencil, paper and a calculator. Calculating sales projections, departmental budgets, engineer- ing estimates, etc. are all done in this manner. PC-Calc combines the familiarity and convenience of a pocket calculator with the powerful memory and electronic screen capabilities of the personal computer. With PC-Calc, the screen becomes a window that shows part of the larger worksheet. You can access different parts of the sheet at will, displaying any 22 by 8 section of the 50 by 20 sheet. The screen is divided into a 22 by 8 grid of rows and columns. The intersection of these rows and columns is called a cell. At each cell you can enter a number, a label, or an equation. In this fashion you can quickly set up your own tables, charts, and records Formatting commands allow you to customize the appear- ance of the data in the worksheet, both on a global and local level. Global formatting applies to all of the cells, while local formatting applies to only to individual cells. (Local formatting takes precedence over global formatting.) In this manner, you can make your spreadsheet look like your bank statement, your income tax form, or your ledger book. The real power of PC-Calc lies in its ability to remem- ber the equations and numbers used as you defined your prob- lem. If you need to change a number on the worksheet, you need merely change that number and PC-Calc will recalculate all the numbers that relate to it. Recalculation makes PC-Calc a powerful tool. This allows the user to easily correct mistakes, as well as examine "whatif" situations. Imagine, for example, that you are doing a sales projec- tion. You may want to know the impact on your company if a specific product does not sell as well as anticipated. What if you sell only 100 cogs instead of 150? What if you sell 500? What if you lose one of your sales personnel and you know that his 35% share of your sales will go with him? These are all examples of "whatif" situations that PC-Calc makes easy to analyze. Whereas it would take the you several hours of erasing and recalculating to do this on paper, once the model was set up, PC-Calc will make the calculations in a matter of seconds. 4 Or perhaps you keep a household budget, and you know that next month there will be an additional 5% tax on gaso- line. With PC-Calc you could look up last month's budget, and with one command multiply all the gasoline charges by 1.05 and use the result as an estimate of next month's budget. To set up these models, you must decide what items you want to show and where you want them on the spreadsheet. After you have decided on a layout, you can enter titles, labels and other textual information to show where the data is to go. Next you enter the raw data such as prices, rates or any other numbers, into the cells you have designated for them. Finally, you enter the equations which will be used to calculate intermediate values and the final numbers you are interested in (i.e. the bottom line). Once you establish the format for a particular applica- tion, you can change the numbers at will. PC-Calc will take care of calculating new answers for the equations based on the new values you just entered, as well as handling the formatting of those cells so that they are displayed in a pleasing and useful manner. PC-Calc is unique in allow- ing you to display numbers either as decimals or fractions. You can save the entire worksheet to a file and recall it later, print the worksheet on the printer to obtain a hard copy, or print a copy to a disk file which you may enter into your word processor as a table. In an hour or two, you can learn enough of the elemen- tary features of PC-Calc to enable you to solve simple prob- lems. As you use PC-Calc and become more familiar with it, you will learn the more advance commands and techniques such as how to have PC-Calc draw a graph of your results. 5 Matrix Introduction 1.1 Screen Format. The PC-Calc matrix is made up of one thousand cells divided into fifty rows and twenty columns. Each cell is displayed as a maximum of eight posi- tions. As a result, only twenty-two rows and eight columns are displayed on the screen. The rows are labeled numeri- cally and the columns are labeled alphabetically, starting at the upper left corner of the matrix. Thus the first cell in the upper left corner would be A1. When the program starts up, it will show cells A1 through H22 on the screen. See the Goto command for information on displaying the rest of the matrix. 1.2 Cursor and Status Line. The current cell is indi- cated by an inverse video cursor. When PC-Calc is first run the current cell will be A1. The top line of the screen is the status line. This line is used to give more informa- tion about the current cell, as well as to prompt the user for more information when executing a Special Command. Values will be shown unformatted in full precision on the status line, although they will have either a global or local format applied to them when displayed in the cell of the matrix on the screen. The global and local formats control how the value is displayed and printed. For more information on the formatting of values, see the Format command. 1.3 Cursor Manipulation. The cursor can be moved to any cell on the screen through the user of the cursor keys to the right of the keyboard. Each time one of the cursor arrow keys is pressed, the current cell changes appro- priately, as indicated by the inverse video cursor. Through these keys, the user is allowed to move the cursor anywhere on the screen. The status line at the top of the screen will change to indicate the contents of the new current cell. The Goto command can be used to move the cursor directly to any cell in the matrix. This command takes a few more keystrokes than the cursor movement keys, but will save keystrokes when moving to a location more than a few cells away. Also, the Goto command allows you to move to a cell that is off the screen. If the cell is off the screen, and the Goto command is used to access it, then the cell will be put at the top left corner of the screen. For more information about the Goto command, see section 2. 6 You may also move the screen window by a full page (screen). On the IBM-PC the PageUp and PageDn keys move the screen 22 lines, while Control left & right cursor move the screen 8 columns. On the Victor 9000 these functions are performed by the SCRL up & down and WORD right & left keys 1.4 Entering Data. The user can enter three types of data into the current cell. The first type of data is a numerical value. To tell PC-Calc that a value is to be entered into the current cell, press the = key. PC-Calc will respond by clearing the status line and prompting you for the value to be entered. You enter a value and press return when done. The status line will again be cleared and PC-Calc will display the new contents of the current cell. The second type of data that can be entered is a label. This is useful for labeling columns or rows of data. To tell PC-Calc that a label is to be entered into the current cell, press the ' key. PC-Calc will respond by clearing the status line and prompting the user for a label. The user enters a label and presses return. PC-Calc will enter the label and display the contents of the current cell. Labels can have up to eight characters per cell. If a longer label is desired, more characters can be entered and the label will be automatically continued into the next cell. The third type of data that can be entered into the current cell is an equation. This is done through the Spec- ial Commands section. For more information on entering equations, see the Equation command in the Special Commands section. 1.5 Clearing the Screen. Occasionally the screen may become cluttered with unwanted material. Or you may wish to clear any highlighted cells back to normal bright- ness. Pressing the HOME key causes PC-Calc to redraw the display. It does not alter the information in any of the cells. 1.6 Cancel. There will be times when you want to stop PC-Calc from updating the screen (which can be slow). For instance, PC-Calc is drawing the screen and you realize that you have another change to make, and then will need to update the screen again. You may press the END key (IBM- PC) or REQuest CANcel key (Victor 9000) and PC-Calc will immediately return control to you. After you make your change you can press the HOME key and PC-Calc will redraw the entire display. 1.7 Quit. To exit PC-Calc enter /Q. 7 Lessons 2.1 Lesson 1. To run the compiled version of PC-Calc (file PC-CALC.EXE) type in PC-CALC <enter>. To run the interpreted BASIC version (PC-CALC.BAS) enter BASIC PC-CALC. The compiled version will run faster but may require more memory. With the interpreted version you can adjust the number of rows and columns to fit you memory size. When you have PC-Calc running, you should see the PC-Calc outline on the screen with rows 1 through 22 displayed on the left and columns A through H displayed across the top of the screen. At the intersection of a row and column is a cell. In each cell, you can enter a label (text), a value (con- stant) or an equation (formula). The top line of the screen is the status line, which gives the contents of the current cell. The current cell is indicated on the screen by inverse video cursor. When the program is first run, the cursor will be in cell A1 and the status line will show "A01 = (blank)", which indi- cates that nothing has been entered into cell A1. This status line is used to display the cell contents and receive user interaction. When PC-Calc is waiting for the user to issue a command, this line will show the contents of the current cell. Movement of the cursor is done through the cursor con- trol keys. To move to cell A2 you would press the down arrow key. To access a cell that is off the screen, use the Goto command. The Goto command is entered by pressing the "." key. PC-Calc will respond by clearing the status line and asking for the cell to which to go. This can be a cell on or off the screen. If it is off the screen, PC- Calc will clear the screen and display a new section of the matrix with the requested cell in the top left corner of the screen, if appropriate. Even for movement on the screen, the Goto command can be easier than the cursor keys if the user has to move more than a few cells. In addressing cells you may specify either A01 or A1 as you please. * * * Practice moving the cursor * * * Moving the cursor and window around are fairly straight forward as you have seen, but so far the worksheet should be empty. Writing on the worksheet is just as easy. Before going further, press the HOME key to clear the screen and rebuild the window on the screen. Now move the cursor to cell A1, press the quote key ('), enter "SALES" and press return. Upon pressing the quote key, PC-Calc responds by clearing the status line and prompting you for the label to go into cell A1. As you enter "SALES", PC-Calc displays it on the status line. The BACKSPACE key can be used to 8 correct any errors before you press the return key, which tells PC-Calc to enter the label in the current cell (A1). Each cell can normally hold up to eight characters. If the label you desire to enter is longer than eight charac- ters, PC-Calc will allow you to enter nine characters in the cell and automatically continue the label in the next cell. (The ninth character goes into the space between the cells.) In this way you can have long titles and labels in the PC-Calc matrix. At this point the status line should read A01=SALES. Now move the cursor to B1 by pressing the right cursor key. When the status line reads B01=(blank), press the = key. This key may be used with or without the shift key being pressed. PC-Calc will prompt the user for a value to go in B1. You can then enter a number up to eight digits long. When you have the number, press return to tell PC-Calc to enter the number in the matrix. Fractions may be entered with a space between the integer and the fractional parts (e.g. 12 3/8). * * * Practice entering Labels and Values * * * To enter an equation, you must go to the Equation com- mand in the Special Command section by pressing the / key. PC-Calc will respond by displaying all the commands available to you in this section. To execute the Equation command press the E key. PC-Calc will then prompt for the Equation to go in the current cell. Equations can have cell referenc- es, numbers, the four math operators (+,-,*,/) and ten levels of parentheses. From cell C1 enter the equation B1+100 and press return. The status line will show the equation you have just entered and its current evaluation. The cell will display this value. If we change the value of B1 we must ask PC-Calc to re-compute the value of the equation in C1. To do this you enter /C which tells PC-Calc to go through the matrix and calculate all of the equations, placing the new values in the cells. In this fashion, the user can make several changes and, when finished with the changes, tell PC-Calc to compute the new values. Since this may take the longest of any of the commands, you should make as many changes as possible before re-computing. At this point, change the value of B1 and press /C. PC-Calc will respond by re- calculating the value of C1 and displaying the new value highlighted so that you can see what happened. You will notice that the cursor disappears while PC-Calc is busy executing your command. It's reappearance is the signal that you may enter your next command. 9 * * * Practice entering equations * * * After entering values, labels and equations into the matrix and computing the results, we can save the PC-Calc matrix as a file so that it can be recalled later. The command to do this is the SAVE command, /S. PC-Calc will respond by prompting for a filespec or name to give to the matrix you are saving. (You are also shown the default file name which will be used if you press enter.) This follows the DOS conventions for naming files and can have the drive prefix as well as the filetype extension. If you do not provide an extension, PC-Calc will use the file- type .CAL to indicate that this is a PC-Calc spreadsheet file. After entering the filespec, PC-Calc will ask you to insert the correct disk for the file, giving you a chance to swap diskettes if needed. After you have saved the matrix to a file, use the LOAD command (/L) to load the file back into the PC-Calc matrix. To indicate clearly that it has worked, we will obtain a new empty matrix first. Execute the NEW command by typing /N. PC-Calc will respond by re-starting from the beginning, with a new, empty matrix. Now execute the LOAD command by typing /L. PC-Calc will ask you for the name of the file to be loaded, just as with the SAVE com- mand. PC-Calc will display the matrix as it is loaded into memory. If you give PC-Calc the name of a nonexistent file an error message will appear on the status line. Press return to recover. The name you give becomes the new default file name. * * * Practice Saving and Loading files * * * The one last command we will cover in lesson one is the QUIT command, which terminates the PC-Calc program. You should make note of the fact that PC-Calc does NOT auto- matically save the data in the matrix when you Quit. It is up to you to save any matrix that you believe is worth keeping. To exit the PC-Calc program type /Q which will return you to the MS-DOS operating system after displaying the credits. 10 2.2 Lesson 2 - In this lesson, you will learn more about the power of Calc, building on the basic principles you have seen so far. We will set up an example and build from there. ----A-------B-------C-------D-------E-------F-------G---- 100 500 1000 2000 3000 5000 A/L RATE 50.00 49.50 45.00 43.00 40.00 39.00 INCL TAX 52.50 51.98 47.25 45.15 42.00 40.95 GP PCT 0.30 0.30 0.30 0.30 0.30 0.30 RATE 75.00 74.25 67.50 64.50 60.00 58.50 GP/100 22.50 22.28 20.25 19.35 18.00 17.55 GP $ 22.50 111.38 202.50 387.00 540.00 877.50 Figure 2.1 Figure 2.1 shows the matrix that we will use to demon- strate the capabilities of Calc. In column A, there is a series of labels for the corresponding rows of informa- tion. In row 1 there is a series of values that label the corresponding columns. First, we will enter the labels in column A. If you do not have a clear screen, press /N to get a New matrix. Move the cursor to A2 and press the quote key to enter a label. Now enter "A/L RATE" and press return. Do the same thing for cells A3 through A7 so that they look like the cells in Figure 2.1. Now use the = key to enter the corresponding values for cells B1 through G1 and cells B2 through G2. At this point all the values in the first two rows are being displayed with two decimal places, even though you entered the top row as simple integers. To get your matrix to look like the one in Figure 2.1 we'll have to use the Format command. In the Format command, there are two options--Global and Local. The Global format applies to all cells which have not yet been assigned a specific Local format. When you assign a cell a Local format, that takes precedence over the Global format. When PC-Calc first starts up the Global Format is two decimal places. In Figure 2.1, row 1 is formatted Locally to Integer. To set the local format for row 1, press /F to execute the Format command, then press L to set a Local format. PC-Calc will now ask if you want the cells displayed as Integer, 0-7 decimal places, or fractions. Enter I for Integer. Now tell PC-Calc that you want this format to apply to the top row of cells by entering B1, press return, enter G1, and press return. At this point your matrix should look like rows 1 and 2 of Figure 2.1 as well as column A. If not, trace back through the first part of the lesson to pick up anything you might have missed. 11 Row 3 of Figure 2.1 is 105% of row 2, (row 2 plus a 5% tax). For this, we will need to enter an equation in B3 to relate this formula to Calc. Move the cursor to cell B3 and enter /E to enter the Equation. Now enter B2*1.05 and press return. B3 now has the correct formula in it, but there are five more cells to fill. Rather than enter the same equation five times, we will use the Replicate command. The Replicate command is used in PC-Calc to copy formu- las, values and labels into a series of cells. In the case of formulas you have the option of copying the formula exact- ly, or relative to where it is placed. To execute the Repli- cate command, enter /R. PC-Calc will then ask you for the source cell. In this case, enter B3 and press return. If your cursor is at B3 you may simply press return and PC-Calc will enter the value of the current cell. PC-Calc will next ask if there is to be a multiple number of cells in the source. Press N for No. If we were going to copy part of a whole row or column we would enter Yes. PC-Calc now asks if the replicate is Absolute or Relative. If we picked Absolute, all of the cells would have the equation B2*1.05 in them, which would be a bit redundant to say the least, thus we want to replicate Relative to the location of the equation. Press R for Relative. Next PC-Calc wants to know where to replicate the equation. You will be prompted for the first and last cells in the target range. Enter C3, return, G3, and return. PC-Calc will now replicate the equation into the cells that we want, and the new equa- tions will reference the cell directly above them, not B2. At this point you should be able to finish off the matrix in Figure 2.1 with the following information. Row 4 is simply the value .30, row 5 is row 3 divided by (one minus row 4), row 6 is row 5 minus row 3, and row 7 is row 6 times row 1 divided by 100. Do not read the next paragraph until you have tried to use the commands we have just covered to duplicate Figure 2.1. If you need a little help, go on to the next paragraph. * * * Enter the rest of Figure 2.1 * * * If you are having problems, here are the equations for column B: B4 = .30 B5 = B3/(1-B4) B6 = B5-B3 B7 = B6*B1/100 * * * SAVE, then practice on this matrix * * * 12 2.3 Lesson 3 - In this lesson, we will learn some of the more advanced features that make entering data into the matrix a bit easier. Load the file back into the matrix that we created in lesson 2. First, we will blank a series of locations with the Blank command. Enter /B and PC-Calc will ask for the series of cells to be blanked. Enter B2, press return, enter G2 and press return. PC-Calc will erases the contents of locations B2 through G2. Now move the cursor to B2. Before re-entering the values we will tell PC-Calc to automatically jump across the row for us. To do this, enter /J and select R for Row. Now whenever a label or value is entered in a cell, PC-Calc will automatically jump to the cell to the right of the current cell. To skip a cell in the row you may simply press return. Try it out by re-entering the values that were in row 2. Next we will examine the print command. When printing, only 8 columns of information will fit on an 80 character wide printer, or 14 columns of information on a 132 character wide printer. PC-Calc will prompt you for the column where you wish to start printing. If your matrix is too wide to print at one time you will have to print it in two or more parts. To print the matrix from the lesson, ready the printer, execute the Print command by entering /P and tell PC-Calc to start with column A. PC-Calc will then print the first 8 or 14 columns depending upon your printer width. To change the printer width we must use the /Z command which changes a number of the PC-Calc default values. These are the maximum number of rows, the maximum number of col- umns, your printer width, print output file or device, and the Bold flag. In each case, PC-Calc shows you the current default and prompts you for a new value. To leave a value as defined you may simply press return. Telling PC-Calc to use fewer rows and columns will greatly increase the speed of operation as PC-Calc will not try to process or display any of the information in the remaining cells. However the cells are still there for you to use by increas- ing the the default values whenever needed. The maximum size of the PC-Calc matrix is set in the program and will appear the first time you enter /Z. These values are usually 50 rows by 20 columns and are limited by the addressing ability of MS Basic. At this time, enter /Z and set the number of rows and columns to 8 each. If you have an 80 column printer you should enter 80 when prompted for printer width. This will prevent PC-Calc from trying to print past the end of your paper. When PC- Calc asks for the name of the print output file or device press return to keep the default device LST (your printer). You could enter a filename and PC-Calc would store the print 13 output for you to print later, or to enter into a word pro- cessor. If you elect to leave the Bold feature ON, values in the matrix which PC-Calc has just computed will be highlight- ed on the screen. For the Total and Average commands, the cells just Totaled will be highlighted. Any command which rewrites the screen (e.g. HOME) will erase the highlighting, as will running the cursor over the cells. If you do not find this feature helpful, use /Z to turn Bold OFF. The next command we will review is the Modify Value command, /M. This command will allow you to perform a calcu- lation on a series of values (not equations) and leave the new value in the cells. It has no effect on equations or labels. For an example, we will increase the values in row 2 by 11% using the Modify Value command. To do this, enter /M, to which PC-Calc will respond "Finish equation :". PC-Calc assumes the value in the cell to be modified to be the first term of the equation, so just enter *1.11 and press return. PC-Calc will then ask for the range of cells to be modified. Tell PC-Calc to use cells B2 through G2. PC-Calc will then modify these values for you. To see the entire results on the whole matrix, enter /C and PC-Calc will use the new values as input to the equations which reference those cells. The Modify Value command can use all of the facilities available in the regular equa- tion mode: cell references, numbers, the four math opera- tors, and ten levels of parentheses. There are two PC-Calc commands which write equations for you. These are the Total and Average commands. To use these commands, move the cursor to the cell where you wish the resulting equation to be placed, then execute the appropriate command, /T for Total or /A for Average. PC-Calc then prompts for the source range for the cells to be totaled or averaged, and places both the equation and the value of the total or average in the current cell. If the Bold feature is ON the source range for the total or average will be highlighted. Two of the most powerful commands at your disposal are the Insert and Delete commands. These commands allow you to make room in the matrix for new data by Inserting a blank row or column or to Delete a row or column without leaving a blank space. When these commands are executed, PC-Calc automatically modifies all equations in the matrix so that they reference the same data, even though it has been moved to a new location. For example, suppose we wanted to add a column labeled 200 between columns B and C of our lesson matrix. To do 14 so, move to column C and execute the Insert command by typing /I and selecting C for column insert. PC-Calc will move all of the columns from C through T one column to the right, losing the data in column T, and creating a new, blank column C. Finally all equations will be altered, such that any reference to (for instance) C5, will now reference D5. The Delete command does just the opposite. To Delete column C, move the cursor to any cell in the column, enter /D and select C to delete a Column. This will cause columns D through T to be moved one column to the left, placing a blank column in column T and deleting column C. Finally all equations which referenced any cell which was moved will be updated to reference the same data in its new loca- tion. Words of caution: be careful when deleting or inserting columns and rows. PC-Calc can easily wipe out a series of values in an instant. The Window command allows the user to display either the row 1 or column A on the screen at all times. For ex- ample, go to cell A50 and execute the Window command, /W, and select the row option by entering R. You will now see row 1 where the top row is. This allows you to place labels for data in row 1 or column A and see them from anywhere in the matrix. The END key (IBM-PC) or REQuest CANcel key (Victor 9000) can be used to save time using PC-Calc by canceling unwanted screen rewrites. Any time PC-Calc is redrawing the entire screen (for example after a GOTO to a cell off the screen, at the end of the /Z command or after you press HOME) you may press the END or REQ CAN key and PC-Calc will immediately stop drawing the screen and be ready to accept a new command. You may also Cancel a Print (/P) or a Compute (/C) command. In the latter case any cells that were not redrawn will still retain their old values. Finally, a word about series. A number of PC-Calc commands (/B, /F, /T, etc.) ask you to enter the first and last cells of a series. Normally these cells will be in a straight line on a row or column. However you may, if you like, enter a block series. For instance, you could use /B to blank out the block of cells C2-C5, D2-D5, and E2-E5 by entering the series C2-E5. PC-Calc considers a block series to be all cells from the starting column to the ending column on each row from the start to the end of the series. In effect, you are entering the upper left and lower right corners of a rectangle. 15 2.4 Lesson 4 - This final lesson will cover a single feature--plotting Bar Graphs. PC-Calc can offer such a feature only with limitations. For one, you can only draw horizontal Bar Graphs. Second, you must scale the graph yourself (i.e. PC-Calc will not automatically scale the graph to fit within a window). Third, if you wish to make the graph smaller, you must manually erase the bars with the Blank command (/B). Fourth, you cannot graph negative numbers. And fifth, the resolution is limited to 1/2 charac- ter width. Despite these limitations, the Bar Graphs you can draw provide a pleasing visual presentation of your results. To draw a Bar Graph, arrange the results to be plotted in a column. In the example shown in Figure 2.2 we have put labels in column A and results in column B. Next, put a single scale factor in column C next to each result to be plotted. This is most easily done by entering the scale factor in the top cell of the column and Replicating it through the rest of the column. The value of this scale factor will depend upon the magnitude of the data and the desired size of the graph. You cannot see the scale factor in Figure 2.2 because the Bar graph is displayed in its place, but the value used in is 15. Also, the bars in Figure 2.2 are drawn with X's. This is not how it will appear on your screen where the bars will be drawn as solid bars. What character you see when you print a bar graph will depend on what printer you own and how it interprets the eight bit code it is sent. ----A--------B--------C--------D--------E--------F--------G-- Putnum Health Fund, Stock Price INCREASE Sun. Increase ---------------------------------------- MAY 1982 0.00 Feb. 27 3.27 XXXXXXXXXXXXXXXXXXXXX Mar. 5 3.72 XXXXXXXXXXXXXXXXXXXXXXXXX Mar. 13 3.89 XXXXXXXXXXXXXXXXXXXXXXXXXX Mar. 20 3.75 XXXXXXXXXXXXXXXXXXXXXXXXX Mar. 27 4.27 XXXXXXXXXXXXXXXXXXXXXXXXXXXXX Apr. 3 4.20 XXXXXXXXXXXXXXXXXXXXXXXXXXXX Apr. 10 3.92 XXXXXXXXXXXXXXXXXXXXXXXXXX Apr. 17 4.67 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Apr. 24 5.06 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX May 8 5.44 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX May 15 5.42 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 0May 22 5.24 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX May 29 5.50 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX June 5 5.54 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX AVERAGE 4.56 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Figure 2.2 16 After you have entered the labels shown in Figure 2.2, and the values in column B and the scale factor 15 in column C, draw the graph by Formatting the scale factors as Bars. To do this, enter /F for Format, L for Local, B for Bar Graph and then the first and last cell addresses of the column of scale factors (C4-C20). PC-Calc will redraw the entire screen, showing the Bar Graph. PC-Calc draws the graph by multiplying the scale factor in the cell formatted as a B by the value in the cell immedi- ately to the left, and then creating a label consisting of that many half-characters wide bars. This label is ex- tended into the cells to the right, as far as the screen permits. The scale factor is retained in the first cell of the Bar graph but is not displayed. (You can, however, see it on the status line.) If the last character in the bar is only a half-character it will be brighter than the rest of the bar. If the graph is not as wide as you wish, you can modify the scale factor in the entire column with the /M command, followed by HOME to redraw the screen. If the graph is TOO wide, first erase the labels extending beyond the scale factors with the /B command and then proceed to modify the scale factors (otherwise parts of the first bar graph will remain in the cells). With a little practice you will find the Bar Graphs very easy to work with and very clear at presenting results. For example, if the cells to be plotted contain equations which are the results of a simulation, you can change the input data, Compute the values of the equations, and Clear the screen to see the results plotted, all in a few seconds. Accompanying this program you will find a file named STOCKS.CAL. Load this file to see an example of using PC- Calc to follow the price of a stock. Press the Control right arrow key (WORD right arrow on the Victor 9000) to move to cell I1 and see a second graph (Figure 2.2), showing the price increase of the same stock. This shows how the Bar graph need not be right next to the part of the spread- sheet that generated the data. You can Replicate the data you want to graph in another section of the matrix and graph it there, or you can graph a column of cells each of which contains the equation making it equal to a cell elsewhere in the matrix. In the latter case you can see the new data graphed whenever you change the old data simply by enter- ing /C to Compute the equations and HOME to redraw the screen. 17 3. Special Commands INTRODUCTION. The Special Commands allow the user to manipulate the contents of the PC-Calc matrix. These commands are accessed by pressing the / key and then select- ing the appropriate command. Any commands that use cell references for source ranges or target ranges apply to cells off the screen as well as on the screen. So you can, for example, replicate to locations off the screen. /A AVERAGE This command allows the user to average a series of cells and put the result in the current cell, as indicated by the inverse video cursor. Thus the user should position the cursor to the cell where he wants the average to appear and type /A. PC-Calc will prompt for the first and last cells you want included in the equation. You should enter each cell when asked and press return. PC-Calc will then write the equation for the average of that series of cells and its value in the current cell. If the BOLD option is on the cells of the series being aver- aged will be highlighted. You may notice that the Average command first displays the total of the range, then changes it to the average. /B BLANK This command allows the user to blank out (erase) a series of cells, either in a row or column. To erase a series of cells press /B and give PC-Calc the starting and ending cells of the series. PC-Calc will erase everything from the cells in the series (values, labels, equations and local formatting). In this as in all other commands, when PC-Calc prompts you for a cell, pressing Return defaults to the current cell. Thus to blank the current cell you could type /B [CR] [CR]. /C COMPUTE PC-Calc will go through the matrix row by row from the top computing and displaying the current values of all equations in the matrix. If the BOLD option is on, each computed value will be highlighted. You may Cancel the Compute command by pressing the END or REQ CAN key. /D DELETE Deletes either an entire row or an entire column. When a column or row is deleted, the following columns or rows are all moved up one location and the new last column or row is left blank. PC-Calc then alters the equations in the matrix to reference the new locations of the cells. To use the Delete command move the cursor to the column or row to be deleted and press /D, then tell PC-Calc whether you want to delete a column or a row. Be careful with this command as you cannot recover the deleted results unless you have previously Saved the matrix. 18 /E EQUATION This command allows the user to enter an equation into the current cell. The user may use numbers with decimals or fractions, cell references, the four main math operators (+,-,*,/) and ten levels of parentheses. To enter an equation type /E, the desired equation for that cell, and return. There are no priorities among the opera- tors. Each is evaluated as it is encountered reading left to right (except for division of one constant by another (e.g. 1/3) which is interpreted as the fraction "one third") Thus 3-1*2 equals 4, not 1, and 5-1/3 is 4 2/3 not (5-1)/3. /F FORMAT This command allow the user to Format the displayed and printed values of the cells. There are two main options to this command--Global formats and Local formats. The Global Format applies to all cells not locally formatted. A Local Format overrides the Global format for that cell. Each cell may be formatted as an Integer, a decimal number with 0 to 7 decimal places displayed, or a fraction rounded to a Half, Fourth, Eighth, Sixteenth or Thirtysecond. To use the Format command type /F and either G for Global for L for Local. Next enter any of the following: I for Integer, 0 thru 7 for that many decimal places, H for Halves, F for Fourths, E for Eights, S for Sixteenths, or T for Thiryseconds. If you chose Local format- ting, PC-Calc will prompt for a series of cells to be format- ted. As usual, you may press return to indicate the current cell. There are several special formatting commands which may be used but which are not mentioned in the Format prompt. If you enter G, PC-Calc will change a locally format- ted cell back to the Global format. If you enter D, PC-Calc will display the current system date. If you enter @, PC- Calc will display the current system time (T is used for fractions). The date and time will always be current up to the last time the cell was displayed. Thus when you re-Load the matrix tomorrow, you will get tomorrow's date and time. If you enter !, PC-Calc will change the value of that cell into a label (i.e. it will no longer be a number or an equation and will not change with /C). This may be used to "freeze" the date and time. A format of type B will cause a Bar Graph to be drawn by multiplying those cells by the values in the cells to the left, and drawing a solid bar of that many half-charac- ters in the current cell and extending to the right. /G GOTO This command allows the user to move the cursor to any cell in the matrix, whether on the screen or off. If the target cell is off the screen, the screen will be cleared and the target cell will be placed in the top left corner, if appropriate. The Goto command can be accessed either as a Special Command (/G) or as a one key- stroke command by pressing ".". 19 /H HELP This command displays a page of one line instructions covering each of the Special Commands. When you are done reading Help press any key to return to your place in the matrix. /I INSERT This command is the compliment of the Delete command. It allows the user to insert either an entire row or an entire column. To execute this command, move the cursor to a cell before which you want a new column or row. Press /I and select either Row or Column. PC-Calc will insert a blank row or column, moving all subsequent rows or columns down one, with the last one dropping off the matrix. Finally, all equations are updated such that all references to cells that were moved are altered to point to the same data. /J JUMP This command sets the Jump mode flag such that whenever the user enters a value with the = key, a label with the ' key, or simply presses the return key, the cursor is moved one cell along the row or column. To use this option type /J, then enter either R to move along the Row, C to move down the Column, or a space to turn off the Jump option. /L LOAD Used to load PC-Calc files saved on disk with the SAVE command. PC-Calc will prompt for a file name. You may enter then entire DOS filespec. If you omit the drive name PC-Calc will use the default drive. If you omit the filetype PC-Calc will append .CAL to the file name. Simply pressing return will load the default filename shown on the status line, which is the last file you Loaded or Saved. /M MODIFY This command allows the user to modify the values of a series of cells. In doing this, PC-Calc will ask you to finish the equation used to modify the val- ues, assuming the value of the cells to be modified as the first term of the equation. Thus to increase a series of cells by 50% and then subtract 10 from them, finish the equation with *1.50-10. Beware of equations such as A1-1/3 which will be interpreted as A1 minus one third, not (A1-1)/3. If the Bold option is ON the modified series will be highlighted /N NEW This command re-runs PC-Calc from the start, clearing all cells and resetting all default values. 20 /P PRINT Prints a section of the matrix on the printer. PC-Calc will print as many columns as will fit in the width of your printer (which you set with the /Z command). An 80 character wide printer will hold columns A-H, a 132 character wide printer will print columns A-N. PC-Calc will prompt for the column with which to start printing. As usual pressing return defaults to the current cursor position. You may also print a copy of your matrix to a disk file, which may then be used as input to a word processor. For this you must change the default file/device name with the /Z command. The /P command will then write an ASCII file which you can display on the screen, copy to your printer, or use as input to another program. You may Cancel the Print command by pressing the END or REQ CAN key. /Q QUIT This is how to exit Calc. Make sure that all data has been saved before Quitting. If you exit PC-Calc in any other manner (i.e. by error or ^C) you will find that your cursor is turned off. To regain the cursor run PC-Calc and type /Q. /R REPLICATE This command allow the user to replicate information from one part of the matrix to another. For values or formulas, this is a regular copy function, but for equations PC-Calc can replicate the equation Relative to its position so that it will reference the correct cells from the row or column of its new position. To use this command type /R. PC-Calc will prompt for the cell to be replicated. You may press return to indicate the current cell. PC-Calc will then ask if there is to be more than one cell used as the source. If you respond with a Y, PC- Calc will increment the source cell replicated from as it steps through the target range. Otherwise PC-Calc will copy only the one cell to all of the cells in the target range. Next PC-Calc will ask if the replication is to be Absolute or Relative. Use Absolute for labels, values and equations that you want to be copied exactly as they are. Use Relative replication for equations which must reference cell in the same position relative to their new location. Finally PC-Calc will prompt for the target range of the replication. /S SAVE This is the compliment of the LOAD com- mand. This command Saves the PC-Calc Matrix as a binary disk file. The user is prompted for a filespec, which can include the drive name and file extension. If you do not specify a file extension PC-Calc will append .CAL to the file name. Pressing return will Save the default file name show on the status line, which is the last file Saved or Loaded. 21 /T TOTAL This command generates the equation for the total of a series of cells and puts the equation and the value in the current cell. Works similar to the Average command. If the Bold feature is ON then the series totaled will be highlighted. /W WINDOW This sets an internal flag which causes PC-Calc to display Row 1 or Column A on the screen at all times. This is used if you have labels in the first Row or Column that you wish to see even if you are displaying a part of the matrix beyond what originally fits on the screen. After typing /W enter either R for row, C for Column or a space to turn off the Window option. You will notice that this option adds some extra time to all commands that change any cell being displayed. /Z This command allow the user to change certain default values used by Calc. PC-Calc will prompt you to enter the Maximum Row and Column you wish to use. Making these numbers as small as needed will greatly increase the speed of Calc, since PC-Calc will not have to display as many cells or calculate the values of unneeded cells. Next PC-Calc will prompt for the width of your printer. Enter the number of characters your printer can handle across the page. PC-Calc will then ask for the name of a file for printed output. For this to go to your printer, leave the default value, LST, by pressing return. To print to a disk file, enter any valid MS-DOS filename such as B:BUDG- ET.TXT. Finally PC-Calc will ask if you want the Bold feature ON or OFF. When Bold is ON PC-Calc will highlight the re- sults of its calculations to distinguish them from con stants. In the Total and Average commands, PC-Calc high- lights the range which was just Totaled or Averaged. This can help avoid mistakes. Clearing the screen returns all cells to normal brightness, as does any other command which rewrites the screen. For all of the above prompts, pressing return will retain the current value. 22 HELP SCREEN /A AVERAGE -generates the equation for averaging a series of cells /B BLANK -erases a series of cells leaving them blank /C COMPUTE -computes all equations /D DELETE -deletes the current Row or Column /E EQUATION -Enters an equation into the current cell /F FORMAT -sets the number of decimal places to be displayed /G GOTO -allows you to goto any cell including those off screen /H HELP -displays these helpful messages /I INSERT -inserts an entire blank row or column before the current cell /J JUMP -causes the cursor to auto. jump across the Row or Column /L LOAD -loads a previously SAVEd PC-Calc file /M MODIFY -modifies a series of cells by an equation you enter /N NEW -reruns PC-Calc from the start /P PRINT -prints as much of the matrix as possible from a given column /Q QUIT -returns you to MS-DOS /R REPLICATE's cells. Equations can be copied Relative to their position /S SAVE -saves the current matrix on disk /T TOTAL -generates the equation for the total of a series /W WINDOW -places Row 1 or Col A on screen at all times (for labels) /Z -changes the maximum Row and Column, and the printer defaults Special Keys: HOME Clr screen; END Cancel; = enter value; ' enter label