!****************************************************
!* THIS IS A TEST PROGRAM I MADE FOR VMS BASIC      *
!****************************************************
PROGRAM UNITCONVERSION
  EXTERNAL REAL FUNCTION GETNUMBER(REAL, REAL)
  DECLARE INTEGER I,F,M     ! For-Next, while variables
  DECLARE INTEGER PMAG,   ! Magnitude pointer  &
                  PUNIT,  ! Unit pointer       &
                  REQMAG, ! Magnitude requested &
                  PRESP,  ! Valid Response matrix point &
                  REQFROM, ! FROM unit &
                  REQTO    ! TO unit
  DECLARE INTEGER INTERACTIVE ! User ask to repeat
  DECLARE REAL    VALUFROM, ! FROM valuese matrix & 
                  VALUTO    ! TO value

  !***********************************
  !* magnitude data
  !***********************************
  ! magnitude code, magnitude name


  DATA 1,"TEMPERATURE"
  DATA 2,"LONGITUDE"
  DATA 3,"MASS"
  DATA -1,"EXIT"

  !***********************************
  !* Unit data
  !***********************************
  ! unit magnitude, factor, delta, symbol, name

  DATA 1,100,273.15,"K","kelvin"
  DATA 1,100,0,"C","celsius"
  DATA 1,180,32,"F","fahrenheit"
  DATA 2,0.001,"mm","milimeter"
  DATA 2,0.01,"cm","centimeter"
  DATA 2,0.0254,"in","inch"
  DATA 2,0.1,"dm","decimeter"
  DATA 2,0.3048,"ft","foot"
  DATA 2,0.9144,"yd","yard"
  DATA 2,1,"m","meter"
  DATA 2,10,"dam","decameter"
  DATA 2,100,"hm","decameter"
  DATA 2,100,"hm","hectometer"
  DATA 2,1000,"km","kilometer"
  DATA 2,1609.3,"mile","mile"
  DATA 2,1853,"n.mile","nautical mile"
  DATA -1,-1,"EXIT","EXIT"

  DIM MAG$ (5)
  DIM MAGCODE%(5)
  DIM UNITMAG%(20)
  DIM REAL UNITFACTOR(20)
  DIM REAL UNITDELTA(20)
  DIM UNITSYMBOL$(20)
  DIM UNITNAME$(20)
  PMAG=0
  PUNIT=0
  M=0
  
  WHILE M<>-1
    READ M
    MAGCODE%(PMAG)=M
    READ MAG$(PMAG)
    PMAG=PMAG+1
  NEXT
  ! Reset PMAG to last valid unit
  PMAG=PMAG-2
  
  
  PUNIT=0
  M=0
  WHILE M<>-1
    READ M 
    UNITMAG%(PUNIT)=M
    READ UNITFACTOR(PUNIT)

    ! Temperature units have deltas
    IF UNITMAG%(PUNIT)=1 THEN
      READ UNITDELTA(PUNIT)
    END IF

    READ UNITSYMBOL$(PUNIT)
    READ UNITNAME$(PUNIT) 
    PUNIT=PUNIT+1
  NEXT
  PUNIT=PUNIT-2 ! Reset PUNIT to last valid unit

  ! Interactive is reserved for compilation as function.
  ! It should return -1 to ask repeat, or 0 to ask exit.
  INTERACTIVE=0

  PRINT "UNIT CONVERSION"
  PRINT "WHAT DO YOU WANT TO CONVERT"
  ! Print a list of magnitudes
  PRINT I;"- ";MAG$(I) FOR I=0 TO PMAG
  PRINT "-1 TO EXIT" 
  REQMAG=INT(GETNUMBER(-1,0+PMAG))
  
  IF REQMAG<0 THEN 
    EXIT PROGRAM
  END IF
  REQMAG=MAGCODE%(REQMAG) !Now ReqMag is a magnitude code.
  
  ! Create a matrix of magnitude units

  DIM RESP%(PUNIT)
  PRESP=0
  
  ! Fill the matrix

  FOR F=0 TO PUNIT
    IF UNITMAG%(F)=REQMAG THEN
      RESP%(PRESP)=F
      PRESP=PRESP+1
    END IF
  NEXT F
  
  PRESP=PRESP-1 ! Reset PRESP to last valid unit.

  ! Show unit list

  PRINT "SELECT UNIT TO CONVERT FROM:"
  PRINT F;"- ";UNITNAME$(RESP%(F)) FOR F=0 TO PRESP
  PRINT "-1 TO EXIT"
  REQFROM=INT(GETNUMBER(-1,0+PRESP))
  IF REQFROM<0 THEN
    EXIT PROGRAM
  END IF
  REQFROM=RESP%(REQFROM) !Now ReqFrom is a unit code.

  ! Show unit list
  PRINT "SELECT UNIT TO CONVERT TO:"
  PRINT F;"- ";UNITNAME$(RESP%(F)) FOR F=0 TO PRESP
  PRINT "-1 TO EXIT"
  REQTO=INT(GETNUMBER(-1,0+PRESP))
  IF REQTO<0 THEN
    EXIT PROGRAM
  END IF
  REQTO=RESP%(REQTO) !Now ReqTo is a unit code.
  
  PRINT "TRANSLATE ";UNITSYMBOL$(REQFROM);" INTO ";UNITSYMBOL$(REQTO)
  PRINT "VALUE TO TRANSLATE: ";
  VALUFROM=GETNUMBER(-9e9,9e9)
   
  ! Translating Temperature? Deltas should be applied, then.
  IF REQMAG=1 THEN
    VALUTO=((VALUFROM-UNITDELTA(REQFROM))*UNITFACTOR(REQTO))/UNITFACTOR(REQFROM)+UNITDELTA(REQTO)
  ELSE
    !These units seem to be reverse defined
    VALUTO=(VALUFROM*UNITFACTOR(REQFROM))/UNITFACTOR(REQTO)
  END IF
  
  PRINT VALUFROM;UNITSYMBOL$(REQFROM);" = ";VALUTO;UNITSYMBOL$(REQTO)
  
  INTERACTIVE=1
END PROGRAM