Option Explicit

Dim A(1 To 100, 1 To 100) As Double
Dim Nrighe As Integer
Dim Ncolonne As Integer
Dim i As Integer
Dim j As Integer
Dim k As Integer

Private Sub Command1_Click()
    Nrighe = txtNrighe.Text
    Ncolonne = txtNcolonne.Text
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf
    For i = 1 To Nrighe
        For j = 1 To Ncolonne
            A(i, j) = InputBox("inserisci il valore a(" & i & "," & j & " ) ")
            TxtRisposta.Text = TxtRisposta.Text & "  " & A(i, j)
        Next j
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf
    TxtRisposta.SelStart = Len(TxtRisposta.Text)
    Next i
End Sub

Private Sub Command2_Click()
Dim Trasposta(1 To 100, 1 To 100) As Double
Dim M As Double
Dim N As Double
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf
    M = Nrighe
    N = Ncolonne
    For i = 1 To N
        For j = 1 To M
            Trasposta(i, j) = A(j, i)
            TxtRisposta.Text = TxtRisposta.Text & "  " & Trasposta(i, j)
        Next j
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf
    TxtRisposta.SelStart = Len(TxtRisposta.Text)
    Next i
End Sub

Private Sub Command3_Click()
    If Nrighe <> Ncolonne Then
        MsgBox ("Per calcolare il determinante la matrice deve essere quadrata"), vbInformation
        Exit Sub
    End If
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf & "Determinante=" & Determinante(A, Nrighe) & vbCrLf
    TxtRisposta.SelStart = Len(TxtRisposta.Text)
End Sub

Private Sub Command4_Click()
Dim N As Integer
Dim M As Integer
Dim i1 As Integer
Dim i2 As Integer
Dim i3 As Integer
Dim j1 As Integer
Dim j2 As Integer
Dim j3 As Integer
Dim det As Double
Dim Inversa(1 To 100, 1 To 100) As Double
Dim B(1 To 100, 1 To 100) As Double
Dim C(1 To 100, 1 To 100) As Double
    If Nrighe <> Ncolonne Then
        MsgBox "Per calcolare l'inversa la matrice dev'essere quadrata.", vbInformation
        Exit Sub
    End If
    det = Determinante(A, Nrighe)
    If det = 0 Then
        MsgBox "La matrice ha determinante nullo.", vbExclamation
    Else
        For i1 = 1 To Nrighe
            For j1 = 1 To Ncolonne
            i3 = 0
                For i2 = 1 To Nrighe
                    If i2 <> i1 Then
                        i3 = i3 + 1
                        j3 = 0
                        For j2 = 1 To Ncolonne
                            If j2 <> j1 Then
                                j3 = j3 + 1
                                B(i3, j3) = A(i2, j2)
                            End If
                        Next j2
                    End If
                Next i2
                If (i1 + j1) Mod 2 = 0 Then
                    C(i1, j1) = Determinante(B, Nrighe - 1)
                Else
                    C(i1, j1) = -Determinante(B, Nrighe - 1)
                End If
            Next j1
        Next i1
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf
    For i = 1 To Nrighe
        For j = 1 To Ncolonne
            Inversa(i, j) = C(j, i) / det
            TxtRisposta.Text = TxtRisposta.Text & "  " & Inversa(i, j)
        Next j
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf
    TxtRisposta.SelStart = Len(TxtRisposta.Text)
    Next i
    End If
End Sub

Private Sub Command5_Click()
Dim E(1 To 100, 1 To 100) As Double
Dim Controllo As Integer
Dim Rango As Integer
Dim P As Double
Dim O As Double
Dim N As Integer
Dim M As Integer
Dim i1 As Integer
Dim j1 As Integer
Dim i2 As Integer
    N = Nrighe
    M = Ncolonne
    For i = 1 To N
        For j = 1 To M
            E(i, j) = A(i, j)
        Next j
    Next i
    j = 0
    For i = 1 To N
        j = j + 1
        If E(i, j) = 0 Then
            For i1 = i + 1 To N
                If E(i1, j) <> 0 Then
                    For j1 = 1 To M
                        E(i, j1) = E(i, j1) + E(i1, j1)
                        E(i1, j1) = E(i, j1) - E(i1, j1)
                        E(i, j1) = E(i, j1) - E(i1, j1)
                    Next j1
                    i1 = N
                End If
            Next i1
        End If
        For i1 = i + 1 To N
            If E(i1, j) <> 0 Then
                P = E(i1, j)
                O = E(i, j)
                For j1 = j To M
                    E(i, j1) = -E(i, j1) * P / O
                    E(i1, j1) = E(i1, j1) + E(i, j1)
                Next j1
            End If
        Next i1
    Next i
    For i = 1 To N - 1
        j = 0
        Do
            j = j + 1
            Controllo = 1
            If E(i + 1, j) = 0 Then
                If E(i, j) <> 0 Then
                    Controllo = 0
                End If
                Else
                    If E(i, j) / E(i + 1, j) <> E(i, j + 1) / E(i + 1, j + 1) Then
                        Controllo = 0
                    End If
            End If
        Loop Until Controllo = 0 Or j = M - 1
        If Controllo = 1 And j = M - 1 Then
            For i1 = i + 1 To N
                For j = 1 To M
                    E(i1, j) = 0
                Next j
                i = N - 1
            Next i1
        End If
    Next i
    Rango = N
    For i = N To 1 Step -1
        j = 0
        Controllo = 1
        Do
            j = j + 1
            If E(i, j) <> 0 Then
                Controllo = 0
            End If
        Loop Until Controllo = 0 Or j = M
        If Controllo = 1 Then
            Rango = Rango - 1
        End If
    Next i
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf
    TxtRisposta.Text = TxtRisposta.Text & vbCrLf & "Rango=" & Rango & vbCrLf
    TxtRisposta.SelStart = Len(TxtRisposta.Text)
End Sub

Private Sub Command6_Click()
    Unload Me
End Sub

Public Function Determinante(Matrice() As Double, N As Integer) As Double
Dim D(1 To 100, 1 To 100) As Double
Dim S As Double
    For i = 1 To N
        For j = 1 To N
            D(i, j) = Matrice(i, j)
        Next j
    Next i
    If N = 1 And D(1, 1) = 0 Then
        Determinante = 0
        Exit Function
    End If
    For i = 1 To N
        If D(i, i) = 0 Then
            k = i
            Do
                If i = N Then
                    k = k - 1
                Else
                    k = k + 1
                End If
                For j = 1 To N
                    D(i, j) = D(i, j) + Matrice(k, j)
                Next j
            Loop Until D(i, i) <> 0
        End If
    Next i
    Determinante = 1
    For i = 1 To N - 1
        For j = i + 1 To N
            S = -D(j, i) / D(i, i)
            For k = 1 To N
                D(j, k) = D(j, k) + D(i, k) * S
            Next k
        Next j
    Next i
    For i = 1 To N
        Determinante = Determinante * D(i, i)
    Next i
End Function