Question

How to sum 2D array (matrix) cols in VB.NET

Answer 1

Module Module1

    Sub Main()

        Dim matrix(,) As Integer = New Integer(,) {{13, 22, 43, 34},
                                                   {43, 54, 67, 98},
                                                   {88, 79, 11, 998}}

        Dim cols_sum() As Integer = New Integer() {0, 0, 0, 0}

        sum_matrix_cols(matrix, cols_sum)

        For i As Integer = 0 To 3
            Console.WriteLine(cols_sum(i))
        Next

    End Sub

    Sub sum_matrix_cols(matrix(,) As Integer, cols_sum() As Integer)

        Dim rows = matrix.GetUpperBound(0)
        Dim cols = matrix.GetUpperBound(1)

        For j As Integer = 0 To cols
            For i As Integer = 0 To rows
                cols_sum(j) += matrix(i, j)
            Next
        Next
    End Sub

End Module

' run:
' 
' 144
' 155
' 121
' 1130

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