Create upper triangular matrix using for loop in matlab

v = 1:6;
n = round((sqrt(8 * numel(v) + 1) - 1) / 2);
M = zeros(n, n);
c = 0;
for i2 = 1:n
  for i1 = 1:i2
    c         = c + 1;
    M(i1, i2) = v(c);
  end
end

I found this code to make an upper triangular matrix, but I don't understand what the code is trying to say to make it work can someone explain to me

[Elizabeth Brito]

Or could you tell me another way to make an upper triangular array with a for loop

[KALYAN ACHARJYA]

MATLAB Onramp