LB Booster: Temperatures converter

Temperatures converter
Post by Optimax on May 11^th, 2017, 09:13am

There must be a lot of such programs out there.
The aim here was to try the method <SUB ButtonHandler handle$>.
I read a very interessant article over this on the Liberty Basic Programmer's Encyclopedia.
Multiple SUBs can be packed together into a single SUB.
I wrote 6 separate functions for the calculations, but as they are only one-line arithmetics, I packed those also in the ButtonHandler.
We need though an extra-SUB 'Quit' for the "trapclose Quit". Here is also a handle$ required, at least in LB4.5.
I noticed also that a number like - 100 produces an error, there must be no space after the minus sign: -100; I was not aware of this this.

Code:

'TEMPERATURES.BAS     LBB 3.07 / LB 4.5        11-05-2017
'================

' Converting temperatures between Celsius (°C), Fahrenheit (°F) and Kelvin (°K)
' Only two variables: T for any input Temperature, R for any conversion Result
' Minimalist GUI for easy code reading

' GLOBAL T, R       'for possible later use

' ---------------- First dimension and center the window, which will be opened later, after creating the buttons

NOMAINWIN
WindowHeight =  600
WindowWidth = 400
UpperLeftX = INT((DisplayWidth - WindowWidth) / 2)
UpperLeftY = INT((DisplayHeight - WindowHeight) / 2)

' ---------------- Create the buttons now before the window opens; they all branch to <SUB ButtonHandler handle$>

BUTTON #w.c2f, "Celsius => Fahrenheit", ButtonHandler, UL, 80, 20,  200, 50
BUTTON #w.f2c, "Fahrenheit => Celsius", ButtonHandler, UL, 80, 90,  200, 50
BUTTON #w.c2k, "Celsius => Kelvin    ", ButtonHandler, UL, 80, 160, 210, 50
BUTTON #w.k2c, "Kelvin => Celsius    ", ButtonHandler, UL, 80, 230, 200, 50
BUTTON #w.f2k, "Fahrenheit => Kelvin ", ButtonHandler, UL, 80, 300, 200, 50
BUTTON #w.k2f, "Kelvin => Fahrenheit ", ButtonHandler, UL, 80, 370, 200, 50
BUTTON #w.out, "E&XIT"                , ButtonHandler, UL, 300, 470, 70, 70    'exits also by pressing ALT-X

' ---------------- Now open the window and wait for a buttonclick

OPEN "Celsius to Fahrenheit to Kelvin" FOR WINDOW AS #w
PRINT #w, "trapclose Quit"

WAIT

' ---------------- And here the ButtonHandler, including the needed simple temperature arithmetics (no functions)

SUB ButtonHandler handle$

Extension$ = RIGHT$(handle$, 3)        'this means the extension "abc" of a button-definition like "BUTTON #w.abc"

SELECT CASE Extension$

    CASE "c2f"
        PROMPT "Convert  C°  to  F°  " + CHR$(13) + "Enter here Celsius degrees :"; T          ''' input Temperature
                IF T < -273.15 THEN NOTICE "Mistake, T°  is below absolute zero !": EXIT SUB   ''' error message
                R = T * 9 / 5 + 32                                                             ''' conversion Result
        NOTICE STR$(T) +" °C converted to °F = " + CHR$(13); R; " °F"                          ''' display Result
    CASE "f2c"
        PROMPT "Convert °F to °C  " + CHR$(13) + "Enter here Fahrenheit degrees :"; T
                IF F < -459.7 THEN NOTICE "Mistake, T° is below absolute zero !": EXIT SUB
                R =  (T -32) * 5 / 9
        NOTICE STR$(T) + " °F converted to °C = " + CHR$(13); R; " °C"
    CASE "c2k"
        PROMPT "Convert °C  to  °K" + CHR$(13) + "Enter here Celsius degrees :"; T
                IF T < -273.15 THEN NOTICE "Mistake, T° is below absolute zero !": EXIT SUB
                R = T + 273.15
        NOTICE STR$(T) + "°C converted to °K = " + CHR$(13); R; " °K"
    CASE "k2c"
        PROMPT "Convert °K to  °C" + CHR$(13) +"Enter here Kelvin degrees :";  T
                IF T < 0 THEN NOTICE "Mistake, T° is below absolute zero !": EXIT SUB
                R = T -273.15
        NOTICE STR$(T) + "°K converted to °C = "; R; " °C"
    CASE "f2k"
        PROMPT "Convert °F  to  °K" + CHR$(13) + "Enter here Fahrenheit degrees :"; T
                IF T < -459.7 THEN NOTICE "Mistake, T° is below absolute zero !": EXIT SUB
                R = (T - 32) * 5 / 9 + 459.7
        NOTICE STR$(T) + "°F converted to °K = " + CHR$(13); R; " °K"
    CASE "k2f"
        PROMPT "Convert °K  to  °F" + CHR$(13) + "Enter here Kelvin degrees :"; T
                IF T < 0 THEN NOTICE "Mistake, T° is below absolute zero !": EXIT SUB
                R = (T  - 273.15) * 9 / 5 + 32
        NOTICE STR$(K) + "K°  to  F° = " + CHR$(13); R; " °F"
    CASE "out"
        CLOSE #w
        END

END SELECT

END SUB

SUB Quit handle$
    CLOSE #handle$
    END
END SUB

Error notifications about coding, style or calculations are sincerely welcome.

Re: Temperatures converter
Post by tsh73 on May 11^th, 2017, 2:39pm

Since all calculations (end error checks) are one-liners it all could be calculated with EVAL

The only problem I seriously don't like these two lines
Code:

    cond$=word$("T < -273.15|T < -459.7|T < -273.15|T < 0|T < -459.7|T < 0", n, "|")
    fml$=word$("T * 9 / 5 + 32|(T -32) * 5 / 9|T + 273.15|T -273.15|(T - 32) * 5 / 9 + 459.7|(T  - 273.15) * 9 / 5 + 32", n, "|")

Code:

'TEMPERATURES.BAS     LBB 3.07 / LB 4.5        11-05-2017
'================

' Converting temperatures between Celsius (°C), Fahrenheit (°F) and Kelvin (°K)
' Only two variables: T for any input Temperature, R for any conversion Result
' Minimalist GUI for easy code reading

' GLOBAL T, R       'for possible later use

' ---------------- First dimension and center the window, which will be opened later, after creating the buttons

NOMAINWIN
WindowHeight =  600
WindowWidth = 400
UpperLeftX = INT((DisplayWidth - WindowWidth) / 2)
UpperLeftY = INT((DisplayHeight - WindowHeight) / 2)

' ---------------- Create the buttons now before the window opens; they all branch to <SUB ButtonHandler handle$>

BUTTON #w.c2f, "c2f", ButtonHandler, UL, 80, 20,  200, 50
BUTTON #w.f2c, "f2c", ButtonHandler, UL, 80, 90,  200, 50
BUTTON #w.c2k, "c2k", ButtonHandler, UL, 80, 160, 210, 50
BUTTON #w.k2c, "k2c", ButtonHandler, UL, 80, 230, 200, 50
BUTTON #w.f2k, "f2k", ButtonHandler, UL, 80, 300, 200, 50
BUTTON #w.k2f, "k2f", ButtonHandler, UL, 80, 370, 200, 50
BUTTON #w.out, "E&XIT"                , ButtonHandler, UL, 300, 470, 70, 70    'exits also by pressing ALT-X

' ---------------- Now open the window and wait for a buttonclick

OPEN "Celsius to Fahrenheit to Kelvin" FOR WINDOW AS #w
PRINT #w, "trapclose Quit"

for i = 1 to 6
    lbl$=word$("c2f f2c c2k k2c f2k k2f", i)
    h$="#w.";lbl$
    #h$  Name$(left$(lbl$,1));" => "; Name$(right$(lbl$,1))
next

WAIT

' ---------------- And here the ButtonHandler, including the needed simple temperature arithmetics (no functions)

SUB ButtonHandler handle$

    Extension$ = RIGHT$(handle$, 3)        'this means the extension "abc" of a button-definition like "BUTTON #w.abc"

    if Extension$ ="out" then
        CLOSE #w
        END
    end if

    fr$=left$(Extension$,1)
    to$=right$(Extension$,1)

    pos=instr("c2f f2c c2k k2c f2k k2f",Extension$)
    n=1+(pos-1)/4   'actually I need word number here. To get words from strings below.

    cond$=word$("T < -273.15|T < -459.7|T < -273.15|T < 0|T < -459.7|T < 0", n, "|")
    fml$=word$("T * 9 / 5 + 32|(T -32) * 5 / 9|T + 273.15|T -273.15|(T - 32) * 5 / 9 + 459.7|(T  - 273.15) * 9 / 5 + 32", n, "|")

    msg$="Convert  ";nm$(fr$);"  to  ";nm$(to$);"  " + CHR$(13) + "Enter here ";Name$(fr$);" degrees :"
    PROMPT msg$; T          ''' input Temperature
    IF eval(cond$) THEN NOTICE "Mistake, ";nm$(fr$);"  is below absolute zero !": EXIT SUB   ''' error message
    R = eval(fml$)                                                             ''' conversion Result
    NOTICE STR$(T) +" ";nm$(fr$);" converted to ";nm$(to$);" = " + CHR$(13); R; " ";nm$(to$)                          ''' display Result

END SUB

SUB Quit handle$
    CLOSE #handle$
    END
END SUB

function Name$(a$)
    Name$=word$("Fahrenheit Celsius Kelvin", instr("fck", a$))
end function

function nm$(a$)
    nm$ = upper$(a$)+"°"
end function

EDIT: got rid of last SELECT CASE in function Name$(a$)

Re: Temperatures converter
Post by Optimax on May 11^th, 2017, 4:08pm

Strong code !
Works fine.
Thanks for your interest.