This program is by Fernando Jannaut and is used here by permission.

This program is supplied without representation or warranty of any kind. Fernando Jannaut and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.

FtIn is an HP 42s program that allows the four basic arithmetic operations (+, -, x, χ) between numbers expressed in Feet, Inches and fractions (up to 1/256 of an inch).

Inside the program the math is performed in inches so the screen shows always in the upper line the results in Feet, Inches and fractions (up to 1/256 of an inch) and in the lower line, the result in inches and decimal fraction. The only exception is when you make a multiplication between two Ft-In distances to find an area; the program shows the result in ft2 and decimal fraction of ft2 in the upper line, and the same area but in in2 and decimal fraction of in2 in the lower line.

The total result of any math is always stored on Reg 00. By entering a distance (pressing XEQ ENT or XEQ F-IN) the contents of Reg 00 is replaced by this new value.

The number 7 on program line No. 19 means a maximum denominator of 2^ (7+1) = 256 which makes the program to work in n/256 of an inch. For example, by changing this number to a 3 the program will work in n/16 of an inch [2^ (3+1) = 16].

ENT + - x χ F-IN

2. To enter a distance in the program, first type in the Feet number (if this is 0 then type 0) and press ENTER, then type in the Inch number (if this is 0 then type 0) and press ENTER, then type in the fraction of an inch numerator (if this is 0 then type 0) and press ENTER, and finally type in the fraction of an inch denominator (if this is 0 then type 0) and then press EXQ ENT; the program will show in the upper line the total distance in Ft-in format and in the lower line the total distance in inches.

Example: Enter a distance of 15-3 5/16

Type Press 15 ENTER 3 ENTER 5 ENTER 16 XEQ ENT: the display will show: 15-3 5/16 X: 183.3125

The lower line shows the distance in inches (183.3125 inches), now the program is ready to do some math with this distance.

3. To enter a second distance, first type in the Feet number (if this is 0 then type 0) and press ENTER, then type in the Inch number (if this is 0 then type 0) and press ENTER, then type in the fraction of an inch numerator (if this is 0 then type 0) and press ENTER, and finally type in the fraction of an inch denominator (if this is 0 then type 0). By doing this you are ready to perform some math.

4. To add (+) or subtract (-) the second number to the first one just press XEQ + or XEQ -, and the total result will be shown in the regular way.

Example: Enter a second distance of 4-11 to be added to the first one

Type Press 4 ENTER 11 ENTER 0 ENTER 0 XEQ +: the display will show: 20-2 5/16 X: 242.3125The lower line shows the total distance in inches (242.3125 inches), and here the program is ready to do some more math with this distance.

It is possible to enter a distance in inches and decimal fraction of inches in the Stack register X and then represent it in the Ft-In format by pressing XEQ F-IN to initiate a new math operation.

Example: Enter a first distance of 71.25 inches.

Type Press 71.25 XEQ F-IN: the display will show: 5-11 1/4 X: 71.25The lower line shows the total distance in inches (71.25 inches), and here the program is ready to do some math with this distance. 5. To multiply (x) the first one by the second one just press XEQ x and the total result will be shown in ft2 and decimal fraction.

Example: Enter a second distance of 4-11 to be multiplied to the first one

Type Press 4 ENTER 11 ENTER 0 ENTER 0 XEQ x: the display will show: 29.19270833333 ft2 X: 4,203.75The lower line shows the total in in2 (4203.75), and here the program is ready to do some math with this area.

6. To divide (χ) the first one by the second one just press XEQ χ, and the total result will be shown in the regular way.

Example: Enter the first distance (5-11 1/4) and then Enter a second distance of 4-11 to divide the first one

Type Press 5 ENTER 11 ENTER 1 ENTER 4 XEQ ENT: the display will show: 5-11 1/4 X: 71.25 4 ENTER 11 ENTER 0 ENTER 0 XEQ χ: the display will show: 1-2 125.830508475/256 X: 14.4915254237

The line shows the total distance in the regular way using up to n/256 of a fraction of an inch. If the figure is too long to fit in the windows then it will scroll down to the lower line. To see the result in inches (14.4915254237) just press EXIT, and here the program is ready to do some math with this number.

7. To add (+), subtract (-), multiply (x) or divide (χ) the first one by a round number just enter the round number and then press +, -, x or χ (using the arithmetic operators of the HP 42s), and the total result will be shown in inches, then to convert this to a f-in and fractions of an in just press XEQ F-IN, the result will be shown in the regular way.

Example: Enter a second number of 4 to divide the first one

Type Press 5 ENTER 11 ENTER 1 ENTER 4 XEQ ENT: the display will show: 5-11 1/4 X: 71.25 4 χ: the display will show 17.8125.To convert this to f-in format, just press XEQ F-IN; the display will show:

1-5 13/16 X: 17.8125The lower line shows the total distance in inches (17.8125 inches), and here the program is ready to do some more math with this distance.

And this is it. Please enjoy this useful routine as I do in my day by day work.

Registers usage: R00 In.######... R01 Ft R02 In R03 Numerator (in.######..) R04 Denominator R05 Exponent of 2 R06 Limit of denominator [2^ (n+1)] R07 UsedAuthor: FERNANDO JANNAUT

Program version: 1.0

Documentation version: 1.0

May 7, 2009

00 { 247-Byte Prgm } 01>LBL 00 02 X/=0? Is X not equal to cero? 03 GTO 02 04 CLX 05 1 06>LBL 02 07 χ 08 + 09 X<>Y 10 12 11 Χ 12 + 13 FS?C 01 14 +/- 15 RTN 16>LBL "F-In" 17 CF 01 18 STO 07 19 7 20 STO 06 21 X<>Y 22 X<0? 23 SF 01 24 ABS 25 12 26 χ 27 IP 28 STO 01 29 12 30 Χ 31 RCL 07 32 ABS 33 - 34 +/- 35 IP 36 STO 02 37 RCL 07 38 ABS 39 RCL 01 40 12 41 Χ 42 RCL 02 43 + 44 - 45 STO 03 46 0 47 STO 05 48>LBL 03 49 RCL 06 50 RCL 05 51 X>Y? 52 GTO 04 53 RCL 03 54 ENTER 55 IP 56 X=Y? 57 GTO 04 58 2 59 STOΧ 03 60 1 61 STO+ 05 62 GTO 03 63>LBL 04 64 RCL 03 65 0.49999 66 + 67 IP 68 2 69 RCL 05 70 Y^X 71 STO 04 72 RCL 01 73 RCL 02 74 RCL 03 75 R^ 76 GTO "Ent" 77>LBL "χ" 78 XEQ 00 79 RCL 00 80 X<>Y 81 χ 82 12 83 Χ 84 STO 00 85 GTO "F-In" 86>LBL "Χ" 87 XEQ 00 88 RCL 00 89 Χ 90 STO 00 91 144 92 χ 93 CLA 94 ARCL ST X 95 |-" ft2" 96 RCL 00 97 AVIEW 98 STOP 99>LBL "-" 100 XEQ 00 101 RCL 00 102 X<>Y 103 - 104 STO 00 105 GTO "F-In" 106>LBL "+" 107 XEQ 00 108 RCL 00 109 + 110 STO 00 111 GTO "F-In" 112>LBL "Ent" 113 CLA 114 FS? 01 115 |-"-" 116 ARCL ST T 117 |-"'-" 118 ARCL ST Z 119 X<>Y 120 X=0? 121 GTO 01 122 |-" " 123 ARCL ST X 124 |-"/" 125 ARCL ST Y 126>LBL 01 127 |-""" 128 X<>Y 129 XEQ 00 130 STO 00 131 AVIEW 132 .END.

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