In Matlab, it is the percent sign.  In FORTRAN, the letter C.  
In Matlab, it is the percent sign.  In FORTRAN, the letter C.  In Pascal, enclosure between parentheses and asterisks.  In Perl, the pound sign.  In C++, double forward slash, or, as in C, enclosure between forward slashes and asterisks.  FTP, what are these symbols in their respective languages?
In Matlab, it is the percent sign.  In FORTRAN, the letter C.  
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