VRC Graphics Calculator Help

Version 1.01


System Requirements
  • The VRC Calculator requires Windows 95 or NT.

  • The Calculator will exceed the boundaries of the 640X480 screen resolution mode. It may still be used in this mode but may require the user to manually scroll the screen. Screen modes 800X600 and 1024X768 work best.

  • The files CalcHelp.html, Contents.html, Body.html and Calc3.jpg are the help files for the calculator. These files must be located in the same directory as Calc.exe. The installation process should locate these files in the correct directory automatically.


    Using The Calculator - Overview
     The layout and basic functions of the VRC Calculator are similar to most other calculators.
    In addition to the common keypad functions the VRC calculator has a menu bar and a graphics display. The menu bar enables the user to
    Load and Save function graphs
    Graphs are saved in the .bmp format. Graphs to be loaded may be .bmp, .gif, .jpg, .ico, .rle, .emf or .wmf files. However, the Load background image option under File is intended to be used solely for loading graphs which have been saved using the calculator. The purpose is to allow the user to superimpose new graphs on previously saved graphs.
    Load and Save macro functions
    Macros are saved as ordinary text files. Although any extension may be used for macro files, VRC recommends using the .mac extention to avoid confusion with other files.
    Change the drawing color
    Access Help screens and
    Exit the progam
    A brief description of almost any calculator function may be displayed by resting the mouse pointer on the function control. For example, when the mouse pointer is placed on the X key the user is informed that the key performs the multiply function.
    The graphic display enables the user to display the graphs of functions defined using the calculator's macro capabilities. The macro functions, located on the main keypad, enable the user to define complex functions and activate them with a single click.

    Basic Calculator Components
     Calculator keys are divided into several, color-coded groups.
    Additionally, the calculator allows direct editing of the Display Window and use of the PC keyboard.

    Digit Keys
     Clicking on these keys has the same effect as pressing on the digit keys of an ordinary calculator. I.e. the digits are copied to the calculator display.
    Clear Keys
    The Clear (C) key
    Clears the display and cancels any pending operations.
    The Clear Entry key (CE)
    Clears the display but retains pending operations.
    Binary Operations
     Binary operations are those which require two numbers. For example, Add (+), Subtract (-), Multiply (X) and Divide (/) are binary operations. Additionally the VRC Calculator implements exponentiation XY as a binary operation.
    For example, to raise the number 3 to the 5th power do the following:
    Enter the number 3
    Press the exponentiation key XY
    Enter the number 5.
    Press the Compute (=) key
    This sequence will cause the result (243) to be displayed on the calculator display.
    Compute (Equal) Key
     The Compute (=) or Equal Key causes any pending computations to be performed and the result to be displayed.

    Memory Keys
     The VRC calculator implements two types of memory functions
  • 1. Simple number storage locations.
    Displayed numbers may be stored in any of 10 memory locations by pressing the STO key followed by one of the ten digits (0-9). Numbers stored in one of these locations may be displayed by pressing the RCL key followed by one of the ten digits.
  • 2. "accumulator" memory functions.
    M+ Add the contents of the display to the accumulator
    M- Subtract the contents of the display from the accumulator
    Min Place the contents of the display into the accumulator
    MC Clear the contents of the accumulator
    MR Display the contents of the accumulator

    Macro Keys
     These keys enable one to define simple or complex functions for two purposes, 1. to simplify the execution of complex computations and 2. to graph functions on the graphic display.

    Unary Operations
     Unary Operations are those which require only one number.
    The Unary operations are the following:
  • Square Root
  • Factorial
  • Square
  • Multiplicative Inverse
  • Additive Inverse
  • Exponential of e
  • Natural log (base e)
  • Log base 10
  • Log base 2
  • Sine
  • Cosine
  • Tangent

    • Two additional keys are grouped with the unary operators.
  • Pi
  • Degrees/Radians

    • Graphic Display Key
     The Graphic Display Key (->) enables or disables the Graphic Display. The Graphic Display displays the graphs of functions. Functions may be defined using the Macro Keys.

    PC Keyboard
     The PC's keyboard may be used to control the VRC Calculator. The +, -, * and / keys on the numeric keypad perform the expected operations as does the X key on the main keyboard. Pressing on he digit keys of the keyboard has the same effect as clicking on the digit keys on the calculator itself.

    Display Window
     The normal function of the Display Window is to display the results of computations. However, the contents of the Display Window may be directly edited by clicking on the Display Window and using the keyboard to type data directly into the Display Window. This may be especially useful when the user wishes to copy a number from another application and paste it into the calculator display.

    Using The Menu
    File
    The File selection on the menu enables the user to
  • Load and Save function graphs
  • Load and Save macro functions
  • (See the Calculator Overview for more detail
    • Options
    Change the drawing color
    Using help
    The help screen is actally a minibrowser. Help information is located in HTML files which are loaded when Help Topics is selected from Help on the menu. Since Help information is in HTML format the user may modify or add Help topics as he/she desires simply by modifying the existing Help files (CalcHelp.html, Contents.html and Body.html) or by creating additional HTML files which may be accessed via the Help browser's BROWSE function. The user may at times wish to "drag" the left side of the Help screen to the right. This will enable the calculator itself to be completely visible while Help topics are also visible. The user will then be able to perform calculator functions while at the same time reading help information on their use. Access to the Help screen "Table of Contents" will be lost in this situation.
    Exit
    Selecting this will exit the Calculator program. This is the recommended method for ending the program.

    Using Macros
    Overview
    Macros enable the user to define complex functions. There are two reasons for using macros in the VRC calculator. The first is to define a complex function as a series of keystrokes so that the function may be executed simply by pressing the Play key. The second reason for defining macros is to define a function to be graphed on the graphics display.
    Creating a Macro (Defining a Function)
    There are three keys (located on the main keypad) used to define and play macros. These are the Record (Rec), Stop and Play keys. The sequence for recording a macro is the following:
    1. Enter a number into the calculator display. The macro function which you wish to define must be able to operate on this number.
    2. Press the Rec key. This will begin the macro definition
    3. Enter a series of keystrokes which computes the desired function.
    4. Press the Stop key
    The macro function is now defined (stored).

    Example: Define the square root of the natural log as a macro function. I.e. when given a number X, this macro will first take the natural log of X (i.e. ln(X)) and then take the square root of the result. Sqrt(ln(X))
    1. Enter the number 5. (5 should now display.) 5 was chosen somewhat arbitrarily. Any number can be chosen so long as the square root of the natuaral log of that number exists.
    2. Press the Rec key. This will begin the macro definition
    3. Press the Ln key.
    4. Press the square root key
    5. Press the Stop key
    The macro function is now defined (stored).

    Playing (Executing) a Macro
    Once a macro is defined it may be played (executed) simply by pressing the Play key. To play the function which takes the square root of the natuaral log of a number (after defining the macro as in the example given above) simply enter the desired number and press the Play key.

    Graphing Functions
    Overview
    The VRC calculator enables the user to draw the graph of any function which can be constructed from the basic functions located on the calculator keypad. Initially the graphic display is hidden but may be revealed by pressing the graphic display key (->) located in the lower right corner of the keypad. Pressing this key while the graphic display is visible will cause the graphic display to become hidden once again. Graphs of functions may be displayed using the following procedure.
    • Reveal the graphic display by pressing the graphic display key.
    • Define the desired function using the macro keys.
    • Set the required graphic parameters such as the min and max values for the X and Y variables.
    • Press the Draw button located in the Graph Controls frame.
    The program will then begin to draw the graph of the stored function beginning with the lowest X value and proceeding to the largest X value.
    Defining a Function
    In order to draw the graph of a function, the function must be defined using the macro keys located on the main keypad. See the section on Using Macros.
    Setting Function Parameters
    The only required parameters are Min X, Min Y, Max X and Max Y. These parameters establish the values which correspond to the minimum and maximum X and Y values on the coordinate axis. They are set by typing the values into the boxes located at the lower left and upper right corners of the coordinate axes.
    Optionally, one may set the number of division marks on the X and Y axes by typing the number of divisions into the boxes labelled for that purpose. By default the number of divisions is set to 100. Every 10th division mark is elongated. If the number of division marks is so large that they cannot be displayed properly then only a subset of the division marks are displayed.
    Drawing the Graph
    Once a function is defined as a macro and the required parameters have been set as explained above, the user need only press the Draw button located in the Graph Controls frame to cause the graph of the function to be displayed.
    Clearing Graphs
    The Clear button locaed in Graph Control frame will clear all graphs drawn in the session. Note that the Clear button will not clear loaded background images.
    Display Coordinates
    If the user clicks on a point on the graphic display the approximate location of the mouse pointer is displayed in the boxes labelled Mouse coords X and Y.

    VRC's Division of Crass Commercialism
    About VRC
    VRC is an association of consultants, computer programmers and software systems analysts with more years of computing experience than we care to admit to.
    VRC Products and Services
    VRC emphasizes the importance of systems analysis by experienced consultants as the first step in software development. VRC specializes in developing custom software solutions from its repository of prototypes. These prototypes include the following:
    • Personnel Staffing
    • Web Site Development
    • Small Law Firm Management
    • Financial Analysis Software
    • Municipal Real Estate and Personal Property Tax Management
    • Data Conversion
    • Survey and Mapping Accessories
    • Queue Analysis
    • Data Encryption
    • Data Structure Implementation and Storage
    • Various Visual Basic database applications

    Contacting VRC
    Email: roussos@lynchburg.edu

    Phone: 804-263-8529

    US Mail:
    C. Roussos
    245 Cabell Mt. Lane
    Arrington, VA 22922

    This program is the property of Constantine Roussos. It may not be sold by anyone other than the owner of the copyright. It may be distributed freely so long as it is not modified in any way and the copyright notice remains intact.

    Send comments, questions, suggestions, etc. to
    roussos@lynchburg.edu.
    This page last updated on June 12. 1997.
    Copyright © VRC