Writing matrix to .dat file

I need to write two sets of data to a .dat file. I have two row vectors, n and an. The index n needs to be written to the value of an. When I attempt this, though, I get all of the n values first and then the an values when I need them in two columns. Here's what I tried.

    % Transforming vectors into column vector formatting
    n = 0:50;
    n = n'

    % Creating matrix to be called and written to .dat
    mat = [n,an];

    %%Exporting data to .dat

    % Creating file to be written to
    fileName = fopen('mat.dat','w');

    % Writing data to file
    fprintf(fileName, '%f %f\n', mat);

    % Closing
    fclose(fileName)

    %Opening file to read
    type mat.dat

I'm not too familiar with this so I'm sure I'm missing something crucial.

Answer 1

[Walter Roberson]

fprintf(fileName, '%f %f\n', mat.');

This is due to the fact that MATLAB accesses data "down" the columns first.

[K Dani]

Ah of course! Thank you so much!