wolffd@0: function l = num2letter(n)
wolffd@0: 
wolffd@0: % map 1:26 to a-z and 27:52 to A-Z
wolffd@0: punct_code = [32:47 58:64 91:96 123:126];
wolffd@0: digits_code = 48:57;
wolffd@0: upper_code = 65:90;
wolffd@0: lower_code = 97:122;
wolffd@0: 
wolffd@0: letters = [char(lower_code) char(upper_code)];
wolffd@0: l = letters(n);