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INTRODUCTION HP 48 Feet-Inch-Fraction, FIF, calculations are made easier with the program described in this Technical Note. Any calculation using or converting decimal formated or FIF formated numbers may be performed. The operating mode is to perform all calculations on the HP 48 just as you would normally except two results are always displayed. The decimal form and the FIF form. A special menu provides convenient entry of inches and the common fractions 1/2, 1/4, 1/8, and 1/16th of an inch. All entries are automaticlly converted to their simplest form. If 60 is entered as inches (IN) the FIF form will show 5' 0" and the decimal form will show 5 displayed as you have set your display mode.
This program is from an EduCALC HP 48 Programming Class assignment. The class was taught by Richard Nelson and Joseph Horn. The program is Joseph's, this description is Richard's. The program structure is also used by the DMS, Degree-Minute-Second, program described in EduCALC Technical Note 63. Create a directory called FIF. Key in the two programs from the listing. One is used to open an environment, the other is used to perform the necessary calculations and display the result at the top of the screen.
USING THE PROGRAM To use the program press the FIF menu key. Two programs will be in the menus - FIF2 and FT2. FT2 is used by FIF2 and is not run by itself. Press FIF2 to open the menu shown below. Note from the display that the program places the machine in user mode. This is a requirement of the vectored ENTER used in the program.
| FT | IN | /2 | /4 | /8 | /16 |
The operation of this environment is to show the number on level one of the stack in labeled FIF form at the top of the display. In this manner you are able to perform any calculations you wish using the menu keys to enter numbers in FIF form and calculating with them in decimal form.
Level one must have a number (zero OK) if you press any user menu key except FT. Any menu key except ENTER or menu FT causes the entered number to be added to the number on the stack. Press zero, FT if zero feet is the case. Once you enter a number on level one of the stack it will also appear at the top of the screen in FIF form with the Label, FIF:, at the left side of the screen. When you are finished with FIF calculations press [NXT] to see:
| EXIT |
Press the EXIT menu key to return to the FIF directory menu.
EXAMPLE PROBLEMS&d@ (Uses FIX two display mode.)
Press L1: FIF Remarks FIF, FIF2 - - Opens FIF environment 15, FT or ENTER 15.00 15' 0" Wall width feet 9, IN 15.75 15' 9" Adds inches 1, /2 15.79 15' 9" 1/2 Adds halves 0, FT 0.00 0' 0" Assumes FIX 2 mode 14, IN 1.17 1' 2" L1: Must have a number 5, /8 1.22 1' 2" 5/8 Adds 5/8 inches 3, X 3.66 3' 7" 7/8 Width of 3 windows - 12.14 12' 1" 5/8 Wall minus windows 4, ö 3.03 3' 0" 7/16 Space between windows
Press L1: FIF Remarks FIF, FIF2 - - Opens FIF environment 35, FT or ENTER 35.00 35' 0" Width feet 4, IN 35.33 35' 4" Adds inches 1, /2 35.38 35' 4" 1/2 Adds halves 2, ö 17.69 17' 8" 1/4 Divides by two ENTER, X 312.85 312'10" 3/16 Squares side 5, FT 5.00 5' 0" Height feet 7, IN 5.58 5' 7" Adds height inches ENTER, X 31.17 31' 2" 1/16 Squares height + 344.02 344' 0" 1/4 Sum of squares û 18.55 18' 6" 9/16 Slope length 2, X 37.10 37' 1" 1/8 Multiply by two 75, FT or ENTER 75.00 75' 0" Building length 8, IN 75.67 75' 8" Adds inches X 2,806.90 2806'10" 13/16* Square feet of roof
* The FIF number here is meaningless. The 10 and 13/16 inches is linear and NOT square inches. Since there are 144 square inches in a square foot 0.9x144=129.6 square inches. Square feet and inch units are not usually mixed.
Press L1: FIF Remarks 0. FT 0.00 0' 0" Start FIF entry 7, /8 0.07 0' 0" 7/8 7/8ths 1, IN 0.16 0' 1" 7/8 Adds Tuesday change 5, /8 0.21 0' 2" 1/2 Adds Tuesday fraction 3, +/-,(*) /8 0.18 0' 2" 1/8 Adds Wed change 1, +/-.(*) IN 0.09 0' 1" 1/8 Adds Thurs units 1, +/-,(*) /2 0.05 0' 0" 5/8 Adds Thurs fraction 1, IN 0.14 0' 1" 5/8 Adds Friday units 3, /8 0.17 0' 2" Adds Friday Fraction 5, ö 0.03 0' 0" 3/8 Calculates average 15, + 15.03 15' 0" 3/8 Selling Price Average
(*) The change sign key, +/-, makes the entry negative for decreases.
Keying In the Programs The programs utilize two advanced programming techniques - Vectored ENTER (áENTER two places in FIF2) and SYSEVALS (two places in FT2). These are not well documented in the User's Guide. If you have questions consult Bill Wickes book (s3BHP 48 Insights Part I(s0B, either S (#2322) or G (#3006) Series Editions. Double check your SYSEVAL addresses because if they are wrong the machine could lock up or corrupt memory. When you have keyed in the programs perform a byte count on them (program object only) to verify that they are the same as listed with the program on the last page of this Technical Note.
Key the programs as listed. Use alpha mode and spell out the commands if you are not familar with their menu locations. The Advanced User's Reference Manual is a must for looking up these commands. One part of FT2 is confusing. The seventh line starts with: SWAP + """... The three double quotes, """, cannot be entered by pressing the quotes key. This is a special case of a string object with a quote inside. If there is an odd number of quotes in a program the machine will attempt to place a missing quote to make it complete. Usually this makes a mess of the program. In order to enter a quote within a string object (a special case because the quote defines the string object) it must be entered as a counted string. To enter, """, use C$ 1 ". Note the space between the $ and 1 and another space between the 1 and the " (quote). Always verify correct program entry with the byte count and check sum given with the program. If you have checked it twice and can't find the error have someone else look at it. More than twice is a waste of your time becuse you are human and are temporarily "blind" to the error.
Program Listings The programs are printed on the 82240B IR printer and enlarged. The byte counts and check sums are included in the data following the listing.