XProfan

WindowTitle "Levenshtein-Distanz (Stringvergleich)"
Cls @rgb(200,200,100)

proc LD' Compute Levenshtein-Distance

    parameters s$,t$
    s$=lower$(s$):var m&=len(s$)
    t$=lower$(t$):var n&=len(t$)
    declare d&[m&,n&],i&,j&,cost&,mi&,c&
    case m& = 0 : return n&
    case n& = 0 : return m&
    i&=0 : while i&<=m& : d&[i&,0]=i& : inc i& : endwhile
    j&=0 : while j&<=n& : d&[0,j&]=j& : inc j& : endwhile
    i&=1

    WHILE i&<=m&

        j&=1

        While j&<=n&

            cost&=1
            case Mid$(s$,i&,1)=Mid$(t$,j&,1):cost& = 0
            mi&=d&[i&-1,j&]+1
            c&=d&[i&,j&-1]+1
            case c&<mi& : mi&=c&
            c&=d&[i&-1,j&-1]+cost&
            case c&<mi& : mi&=c&
            d&[i&,j&]=mi&
            inc j&

        EndWhile

        inc i&

    ENDWHILE

    return d&[m&,n&]

Endproc

' Input Loop
declare str1$,str2$

While 1

    Locate 10,10 : print "String1  =                                   ";
    Locate 12,10 : print "String2  =                                   ";
    Locate 14,10 : print "Ergebnis =                                   ";
    Locate 10,21 : input str1$ : case str1$="" : End
    Locate 12,21 : input str2$
    Locate 14,21 : Print LD(str1$,str2$)
    WaitInput

EndWhile

END