fopen sometimes not writing all message and saved?

Hi everyone!!!

I have SDP for encrypted and decrypted message but sometimes not save all encrypted message.

for example:

S is encrypted message.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
S=`@ `!@  AA  C@@@ACCACACCAEAEEAAEEEIIEAIAAYIYAIIAAAAaaAqaAaaAaA!aA!!AA
fh=fopen('tower.txt','w');
fprintf(fh, '%s' ,S);
fclose(fh);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

but tower.txt file has just

 `@

please tell me

why not save all?

and how to solve it?

thank you

Answer 1

[Walter Roberson]

fprintf() stops at NUL characters inside strings. That is, it stops at characters with value binary 0. This has to do with the fact that the underlying libraries treat binary 0 as the marker for end of string (this is a design that goes back numerous decades.)

You should not use fprintf() for what you are doing.

fwrite(fh, S);

[Mohammed alajaji]

thank you so much