An
Analysis utility for your Petrol and Oil Consumption
Program
Requirements 48K DISK
Formatting data for screen display is a very
powerful feature of Atari basic. It is well known that the tab stops
on the screen can be changed and reset from within a string. Apart
from formatted display, formatted input can be produced in the same
way. By far the easier method of changing tab stops is by the use of
strings. Once the strings are set up, they need only be printed to the
screen to produce the desired results. There is one other method,
which is to poke in directly the values required. This technique is
used in the main program presented here. The decimal locations 675 to
689 control all the tab locations on the screen display. The screen is
40 columns across and each of the above locations controls eight bits
or eight potential tabs on it. The reason there are so many locations
is that they control one logical line, or three screen lines. To
change the tabs for display, only the first five locations need be
changed. To cancel all tabs a zero is into poked each location. If a
zero is poked into 675 then there would be no tab in the first eight
columns (00000000). If the same was done with location 676 then the
first two bytes or 16 bits or 16 screen columns would look like this,
0000000000000000. This means:
Location 675
controls columns 0 to 7
Location 676
controls columns 8 to 15
Location 677
controls columns 16 to 23
Location 678
controls columns 24 to 31
Location 679
controls columns 32 to 39
If you wish to place a tab stop in column 25 then
you must use location 678. However there is a problem, supposing you
want to set tab stops at columns 25, 27 and 30, how do you do it? The
answer is that the eight tab stops covered by each location is really
a binary number. The decimal equivalent must be poked into that
location. If we wish to have tab stops at columns 25, 27 and 30, the
eight bits or single byte covered by 678 should look like this,
01010010. There is a one at each tab position. We need to poke the
decimal equivalent into location 678. In this case the value that must
be poked into 678 is 82. To reset the default tabs press system reset.
The tab stops should not be confused with PTABW location 201, which
controls the distance between print statements using commas. Once the
tab positions are set, the cursor can be moved to each position by
pressing the [TAB] key.
It is not the purpose of this article to delve into
conversion of binary to decimal, but before I continue with details of
the program I will say that a good conversion utility
(BINARY-HEX-DECIMAL) can be found in Mapping the Atari, a Compute!
publication.
PLANNING THE PROGRAM
Before starting any programming project such as this it is very
important to have a clear objective in mind. Even before the planning
starts there must be a clear idea of what is to be achieved and if
possible how. Only then can any program begin to take shape in the
mind. This is particularly important if you do not want things to come
to a sudden halt, when the ideas run out, or the results do not turn
out as expected.
The first thing to do is to ask yourself a series of
questions. They usually begin with "What do I want the program to
do". In the case of Autocar this was easy but "What is the
best way of analysing your cars petrol consumption" was a little
harder. Further questions come to mind like "How much does the
tank hold" and "Will I run out of petrol if I run the tank
too low." These questions are relevant because you need to know
how much fuel is used. Happily there is a simpler answer to all this
confusion.
When you next fill up with petrol, and I mean FILL
UP or the system will not work. Make a note of the DATE, QUANTITY,
PRICE and clock mileage. Enter the data into the program. When you
next decide to visit a petrol station make a note of the details again
and ENSURE that the tank is filled. The amount now replaced in the
tank is totally representative of the mileage covered. Continue with
this until a number of data entries have been made. The program will
show clear differences between the consumption for town work, medium
distances, and motorway long hauls. There are still inaccuracies using
this method but over a period of time, the true facts will emerge.
If when buying petrol you do not fill the tank, then
save the details and add them together before entering them into the
program, with the clock mileage at the time of the last fill up.
REMEMBER before using this addition method, you must have completely
filled the petrol tank at the point at which you decide to enter the
details, otherwise the results will be meaningless.
SUMMARY OF THE PROGRAM FUNCTIONS
There are two program listings for Autocar. The main
listing is here and the second listing covering the graph functions
will appear next issue. The programs enable the user to enter the
clock mileage, the date, the quantity in gallons, or pints, and the
cost. The programs will then analyse costs and consumption, in figures
or graphical form. The graph option has been disabled in this first
listing but the program can be used as it stands.
The program features ANALYSIS BETWEEN ANY TWO DATES and ANALYSIS OF
ALL DATA. The average values are given for MILES/GALLON or MILES/PINT
and PRICE/GALLON or PRICE/PINT. Totals are given for MILES COVERED,
GALLONS OR PINTS CONSUMED and COSTS.
PROGRAM OPERATION
Anyone who is only interested in entering the
program, and using it, should first read the PLANNING section, in
order to obtain practical information on the use of Autocar.
GETTING STARTED
The listing in this issue is the main program. Type
it in carefully, using TYPO II if you have a copy, and save the
program to disk using SAVE"D:CAR". Before running the
program delete line number 200. Run the program. The main menu
will now appear. The program will not allow any selection to be made,
from this menu, until Oil 'O' is pressed, or Petrol 'P' is pressed.
The main menu will now display the selection made at the top of the
screen.
Creating the disk data file: Select option
'7' from the main menu. The computer will now save a data file to
disk. The data for both Oil and Petrol are saved together in the same
file. Re - enter line number 200, or re-load the program from disk
Every time the program is now run, all data
previously saved by it will be automatically loaded, before the main
menu appears.
USING THE PROGRAM
Data is entered and saved using the program in this
issue. The graphics program to be published next issue will chart the
data entered from program one. Both programs will be chained together
on the disk drive. Each program runs the other. It is therefore
important that the correct filenames are used for each, when saving
them to disk. Listing one should be saved using SAVE"D:CAR",
while SAVE"D:GRAPH" should be used when you add the GRAPH
listing.
1 .. ENTERING DATA
When this option is selected the next screen will
ask for 'E'-EXIT or `D'-ENTER DATA to be pressed. Exit will return the
program to the main menu. If data entry was selected the screen will
go blank for some seconds and the next screen will show a formatted
data entry including ENTRY No., DATE, MILES, GALLONS (or PINTS) and
PRICE. The entry number will already be displayed at the far left of
the screen. Make the entries in each field in the format shown above
each field title. After each entry press the `TAB' key. The cursor
will now jump to the next field. Continue this process until the last
field is reached. After the entry in the last field, do not press the
`TAB' key, press `RETURN. At the bottom of the screen the option to
add more data `A' or to exit `E' will be given. Exit will return the
program to the main menu. If the add option is chosen the cursor will
update the available memory at the top of the screen, and return to
directly under the previous entry, where the process may be repeated.
The new entry number will also be displayed. When the screen is filled
with data entries, the program will clear the screen and give the
option to exit, or make further entries.
2 .. DELETE DATA
This routine asks for a simple date entry in the format of MMDDYY, as
displayed on the screen. Enter the date and press RETURN. If the entry
is not found the program will ring the bell, and the option to
re-enter the date or to exit, will be given. If the date entered here
is found the data will appear instantly. A machine language subroutine
is used in the program to provide such a fast response. When the entry
is found the choice to continue search, exit or re-enter the date will
be given. The continue search option is provided on the slim chance
that two dates which are the same may be in the records. This could
happen if a long journey is involved, or the date was entered
incorrectly in the first place. If delete data has been chosen
(SELECT) the program will display, 'ERASING DATA PLEASE WAIT'. After
deleting the data, if it occurs in the middle of the file, a gap will
now exist. The program will now take a few more seconds to close this
gap (CONCATENATE THE FILE). If the entry which was deleted was in in
the middle of the file and it is necessary to replace it in a similar
position, OPTION 6, the insert data routine must be used from the main
menu. (SEE 6.. INSERT/DELETE ALL DATA).
3 .. VIEW DATA
This part of the program is a series of routines, to
display the data entries to screen. Among the options are; STEP
THROUGH DATA, SINGLE DATA SEARCH and DATE RANGE OF DATA
Step through data: This routine will display
all data to the screen.
Single data search: This selection will
require a single date entry. `END OF SEARCH PRESS ANY KEY', will
appear. If the entry was found, it will appear instantly. If not, then
nothing will be displayed.
Date range of data: The purpose of this
option is for the user to enter a range of dates, between which the
program will display all data. (DATE1 & DATE2). The dates which
are entered for these may be dates which are not
actually in the records. The program will still display all data
entries between them.
4 .. PRINT DATA
This option will print all data in the memory to the
printer. SEE PRINTER SUPPORT, for more information.
5 .. SPECIAL CALCULATIONS
Among the options given in this set of routines are
ALL TOTALS AND AVERAGES, GRAPHICAL ANALYSIS, and COST ANALYSIS.
All Totals and Averages: This routine can, if
used correctly, be the most useful in the whole program. The program
prompts the user to enter two dates. The first date must be earlier
than the second. If RETURN is pressed without entering anything for
either prompt the program will default to analysing all the data
entries in the memory. The instructions for using this routine are
clearly shown on the screen. Whatever combination is used, the dates
entered, must be dates actually in the records, or the program will
again default to analysing all data. If the results are unexpected,
check your dates by using option 3 from the main menu, VIEW DATA or,
if you have a printer, option 4 PRINT ALL DATA.
The first choice is to press RETURN for the first date, and enter the
second. The program will then analyse all data up to that date. Choice
two is the reverse, enter date one, and press RETURN for the second
date. The program will then analyse all data from the date entered, up
to the last entry. If both dates are entered then the program will
analyse any entries between them. All results may be sent to the
printer.
Graphical Analysis: If 2 is pressed, the
computer will load, and run the graphing program (to be published next
issue).
Cost Analysis: Before selecting this part of
the program, whether for oil or petrol, ensure that more than one data
entry is in the program, or the display will be blank.
The program will analyse the data between each pair
of entries, giving the dates, (datel to date2,date2 to date3), the
mileage between them, the corresponding consumption in MILES/GALLON or
MILES/PINT and the COST/ GALLON or COST/PINT. These last two items are
shown in graphical form if GRAPHICAL ANALYSIS is chosen.
All results may be sent to the printer.
6 .. INSERT/DELETE ALL DATA
When data is entered into the program using option
one, it is not sorted into date order. The enter data routine assumes
that each successive date is later than the first. The insert routine
presented here will insert data between existing entries. This will be
carried out according to date and mileage. It must follow that if a
date entry neatly fits in chronological order, between two existing
entries, the clock mileage must also fit in at the same point. However
for long journeys, the petrol tank could be filled up twice on the
same day. This will also be taken into account If the program will not
accept any entry in which the date is later, insert the new entry with
reference to the mileage. The program will not except any entry in
which the date is later, or the mileage greater, than the last entry.
The last entry will be displayed.
One further point should be made about this routine,
and that is that the greater the number of entries, the longer this
process will take.
Delete all Data: The purpose of this routine
is that once the memory is full, all the records may be cleared to
start again.
7.. SAVE DATA TO DISK
This option is used to save oil and petrol records
to disk It should be used after any new data entries are made. I
recommend that you keep at least one backup copy of your data file on
another disk.
8 .. LOAD DATA FROM DISK.
This part of the program maybe used to re-load a
data file from disk. It may also be used to load different data files,
for example, for another vehicle. When a different data file is
loaded, any previous file will be erased.
PRINTER SUPPORT
All printer output is tailored to forty columns. The
program supports output to an 80 column dot matrix printer. As
presented the code is designed for forty column DOUBLE WIDTH output
for the Epson type of printer. If you have a dot matrix printer and
the codes are not compatible with the Epson, then you will have to
change lines 6000 and 7400 in the program to the appropriate codes for
your printer. If your printer is not dot matrix then alter lines 6000
and 7400 to TRAP 9000 only.
LINE BY LINE
| 3 - 200 |
INITIALISATION |
| 500 - 770 |
MAIN MENU & SELECTION ROUTINES |
| 780 - 1330 |
ENTER DATA ROUTINE |
| 1340 - 1420 |
VIEW DATA MENU & SELECTION |
| 1425 - 1508 |
SINGLE STEP THROUGH DATA |
| 1510-1640 |
SINGLE DATA SEARCH |
| 1650 - 1800 |
DELETE DATA ENTRY ROUTINE |
| 1810-1970 |
DELETE DATA ROUTINE |
| 1980-2170 |
RANGE OF DATA ROUTINE |
| 3000 - 3140 |
SPECIAL CALCULATIONS MENU |
| 3142 - 3258 |
CALCULATION OF TOTALS &
AVERAGES |
| 3265 - 3350 |
DISPLAY RESULTS |
| 4000 - 4030 |
STRING SEARCH ROUTINE |
| 5000 - 5020 |
SAVE DATA ROUTINE |
| 5030 - 5060 |
LOAD DATA ROUTINE |
| 6000 - 6130 |
PRINTER ROUTINE |
| 7000 - 7340 |
COST ANALYSIS |
| 20000 - 20150 |
DATA FOR STRING SEARCH ROUTINE |
|
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