how can i print arrey in matrix mod?

Code like I've used in the following console application will give you a display similar to what you might get if you were drawing the matrix on a piece of paper:

using System;
using System.Text;

class Test
{
    static void Main()
    {
        int imax = 3; // say
        int jmax = 4; // say
        double[,] mat = new double[imax, jmax];

        // fill matrix with some arbitrary data
        for (int i = 0; i < imax; i++)
        for (int j = 0; j < jmax; j++)
           mat[i,j] = ((i + 1) * (j + 1)) / 4.0;
       
        // build matrix string representation
        // field width of 5 and 2 decimal places assumed
        const char Vertical = '\u2502';
        const char UpperLeftCorner = '\u250c';
        const char UpperRightCorner = '\u2510';
        const char LowerLeftCorner = '\u2514';
        const char LowerRightCorner = '\u2518';

        StringBuilder sb = new StringBuilder();
        sb = sb.Append(UpperLeftCorner);    
        sb = sb.Append(new string(' ', jmax * 7));
        sb = sb.Append(UpperRightCorner);
        sb = sb.Append(Environment.NewLine);    

        for (int i = 0; i < imax; i++)
        {
           for (int j = 0; j < jmax; j++)
           {
              if (j==0)
              {
                 sb = sb.Append(Vertical);
                 sb = sb.Append(" ");
              } 
              sb = sb.Append(String.Format("{0,5:F2}", mat[i,j]));     
              if (j < jmax - 1)
                 sb = sb.Append(", ");
              else
              {
                 sb = sb.Append(" ");
                 sb = sb.Append(Vertical);
                 sb = sb.Append(Environment.NewLine);
              }               
           }
        }

        sb = sb.Append(LowerLeftCorner);    
        sb = sb.Append(new string(' ', jmax * 7));
        sb = sb.Append(LowerRightCorner);    

        string matrixString = sb.ToString();
        Console.WriteLine(matrixString);
    }

}