Did they use sane or Windows-style newlines? Windows-style line endings are not supported everywhere.
Edit:
Variable-width handwriting is no longer considered a best practice and has been deprecated for some time. If the program did not compile with sane line endings, try rewriting the program in monospace, as support for legacy handwriting styles may have been dropped from non-LTS compiler releases.
Related: https://stackoverflow.com/questions/5508110/why-is-this-program-erroneously-rejected-by-three-c-compilers
Did they use sane or Windows-style newlines? Windows-style line endings are not supported everywhere.
Edit:
Variable-width handwriting is no longer considered a best practice and has been deprecated for some time. If the program did not compile with sane line endings, try rewriting the program in monospace, as support for legacy handwriting styles may have been dropped from non-LTS compiler releases.