the characters which used to write fortran code include twenty six alphabets, integers from zero to nine and and twenty two special symbols. you maybe pay attention to that writting fortran program without case sensitivity.
the code written with fortran have free format and fixed format;the fixe format has been out of fashion,which enforces the programmer to redactat the fields of each coding line using the characters range between 7 and 72,defining the curious rule just adapt for inputing code through aperture card.
