How to write ASCII characters corresponding to decimal numbers into a file?

I get some special symbols for large arrays and for small arrays I could write the characters.

[Dyuman Joshi]

a=65;
b=char(a)

b = 'A'

[RENJI]

Thank you very much.

Answer 1

[Jan]

This writes the character 'A' at the current file position:

n = 65;
fwrite(fid, n, 'char')