Dim x(50), y(50), a(9), b(9), a1(9), b1(9), d(9), v(2, 3), xy(9), vm(2, 3)
Dim vc(2, 3), lo(2, 3), lxy(9), r$(9)
Dim i, c%, j, k, l$, titre$, n, bidon, f$, l, m, xx, yy
Data "A+B*X","A*B**X","1/(A+B*X)","A+B*LOG(X)","A*X**B"
Data "1/(A+B*LOG(X))","A+B/X","A*B**(1/X)","X/(A+B*X)"
For i = 1 To 9
  Read r$(i)
Next i
Erase x(), y(), lxy(), lo()
choix:
Cls
Print AT(30, 1); "CURFIT"
Print AT(30, 6); "Type d'entr‚e des donn‚es "
Print AT(30, 9); "1 Clavier"
Print AT(30, 11); "2 Data"
Print AT(30, 13); "3 Fichier"
Print AT(30, 19); "votre choix ";
Input c%
Cls
Select c%
Case 1
  ' Les entr‚es se font au clavier
  Print AT(24, 5); " Entr‚e des donn‚es au clavier"; AT(1, 8)
  Line Input "Titre : ";titre$
  Print
  Input "Nombre d'observations : ";n
  Dim x(n), y(n), lxy(9), lo(2, 3)
  Print
  Print "Abcisses : ";
  Line Input l$
  j = 1
  l$ = l$ + ","
  For i = 1 To n
    k = InStr(l$, ",", j)
    x(i) = Val(Mid$(l$, j, k - j))
    j = k + 1
  Next i
  Print
  Print "Ordonn‚es : ";
  Line Input l$
  j = 1
  l$ = l$ + ","
  For i = 1 To n
    k = InStr(l$, ",", j)
    y(i) = Val(Mid$(l$, j, k - j))
    j = k + 1
  Next i
Case 2
  ' Les entr‚es se font par DATA
  ' Titre
  Data  Facturation Internet le 9
  ' Nombre d'observations
  Data 12
  Data 24.533,0.345,0.340
  Data 16.033,0.260,0.264
  Data 35.950,0.460,0.443
  Data 7.850,0.179,0.190
  Data 0.583,0.106,0.126
  Data 16.867,0.269,0.271
  Data 6.950,0.170,0.182
  Data 0.333,0.103,0.123
  Data 18.250,0.283,0.283
  Data 10.583,0.206,0.215
  Data 14.800,0.248,0.252
  Data 7.333,0.173,0.185
  Read titre$, n
  Dim x(n), y(n), lxy(9), lo(2, 3)
  For i = 1 To n
    Read x(i), bidon, y(i)
  Next i
'##E#
Case 3
  ' Les entr‚es se font par fichier texte
  ' Structure du fichier :
  '
  ' Titre
  ' Nombre d'observations
  ' Abcisses
  ' Ordonn‚es
  '
  FileSelect "\*.crf", "", f$
  If f$ = "" Or f$ = "\"
    GoTo choix
  EndIf
  Open f$ for Input As # 2
  Line Input # 2, titre$
  Input # 2, n
  Dim x(n), y(n), lxy(9), lo(2, 3)
  For i = 1 To n
    Input # 2, x(i)
  Next i
  For i = 1 To n
    Input # 2, y(i)
  Next i
Default
  GoTo choix
EndSelect
' v(1,*)= f(x) v(2,*)=y  v(*,1)=x ou y  v(*,2)=log(x ou y)  v(*,3)=1/( x ou y)
For i = 1 To n
  v(1, 1) = x(i)
  v(2, 1) = y(i)
  If lo(1, 2) = 0
    If x(i) <= 0
      lo(1, 2) = 1
      Rem Calcul impossible
    Else
      v(1, 2) = Log(x(i))
    EndIf
  EndIf
  If lo(1, 3) = 0
    If x(i) = 0
      lo(1, 3) = 1
      Rem Calcul impossible
    Else
      v(1, 3) = 1 / x(i)
    EndIf
  EndIf
  If lo(2, 2) = 0
    If y(i) <= 0
      lo(2, 2) = 1
      Rem Calcul impossible
    Else
      v(2, 2) = Log(y(i))
    EndIf
  EndIf
  If lo(2, 3) = 0
    If y(i) = 0
      lo(2, 3) = 1
      Rem Calcul impossible
    Else
      v(2, 3) = 1 / y(i)
    EndIf
  EndIf
  k = 0
  For l = 1 To 3
    For m = 1 To 2
      vm(m, l) = vm(m, l) + v(m, l)
      Rem Somme
      vc(m, l) = vc(m, l) + v(m, l) ^ 2
      Rem Somme des carr‚s
    Next m
    For j = 1 To 3
      k = k + 1
      lxy(k) = lo(1, l) + lo(2, j) - lo(1, l) * lo(2, j)
      Rem Calcul possible ?
      If lxy(k) = 0
        xy(k) = xy(k) + v(1, l) * v(2, j)
        Rem Somme des produits
      EndIf
    Next j
  Next l
Next i
k = 0
For i = 1 To 3
  For m = 1 To 2
    If lo(m, i) = 0
      vc(m, i) = vc(m, i) - vm(m, i) ^ 2 / n
    EndIf
  Next m
  For j = 1 To 3
    k = k + 1
    If lxy(k) = 0
      xy(k) = xy(k) - vm(1, i) * vm(2, j) / n
    EndIf
  Next j
Next i
k = 0
For i = 1 To 3
  For j = 1 To 3
    k = k + 1
    If lxy(k) = 0
      b(k) = xy(k) / vc(1, i)
      a(k) = (vm(2, j) - vm(1, i) * b(k)) / n
      d(k) = b(k) * xy(k) / vc(2, j)
    EndIf
  Next j
Next i
For i = 1 To 9
  a1(i) = a(i)
  b1(i) = b(i)
Next i
For i = 2 To 8 Step 3
  a1(i) = Exp(a(i))
  b1(i) = Exp(b(i))
Next i
b1(5) = b(5)
b1(9) = a(9)
a1(9) = b(9)
Print Tab((80 - Len(titre$)) / 2); titre$
Print
Print "             LISSAGE SUIVANT 9 COURBES DIFFERENTES"
Print
Print "NO", "FONCTION", "A", "                             B", "                             D"
For i = 1 To 9
  If lxy(i) = 1
    Print Using("##   Y=\............\   CALCUL IMPOSSIBLE", i, r$(i))
  Else
    Print  i, r$(i), a1(i), b1(i), d(i)
  EndIf
Next i
Do
  Print
  Repeat
    Input "DETAIL POUR FONCTION NO : ( 0 pour finir) ? ", l
  Until l >= 0 And l < 10
  Exit If l = 0
  Print "FONCTION Y="; r$(l)
  If lxy(l) = 1
    Print " CALCUL IMPOSSIBLE"
  Else
    i = Int((l + 2) / 3)
    j = l - (i - 1) * 3

    Print "X-REEL", "Y-REEL", "Y-CALC", "                             DIF", "                             DIF%"
    For k = 1 To n
      xx = x(k)
      Select i
      Case 2
        xx = Log(xx)
      Case 3
        xx = 1 / xx
      EndSelect
      yy = a(l) + xx * b(l)
      Select j
      Case 2
        yy = Exp(yy)
      Case 3
        yy = 1 / yy
      EndSelect
      Rem d = (y(k) - yy)
      Rem p = d * 100 / yy
      Print x(k), y(k), yy, y(k) - yy,(y(k) - yy) * 100 / yy
    Next k
  EndIf
Loop