C# is the sharp note above C, enharmonic with D flat in a tempered tuning.
No, it's not. C♯, with a sharp sign, is the sharp note. Exchanging the number sign for the sharp sign is like exchanging the Latin capital letter R for the Cyrillic capital letter Ya (Я).
Fortran gets a pass for being ancient and having a descriptive name (FORmula TRANslation)