Or, more formally, addition is commutative but subtraction is not. A + B always* equals B + A, but A - B generally does not equal B - A.
*Is that true for computer languages (as opposed to being true only for pure math)? In modern C++ if I say auto x = y + z; If y and z are of different types (float and integer; 64-bit and 32-bit) does x take the type of the first operand, and thus y + z yields a different result than z + y? Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Bernd Oppolzer Sent: Saturday, July 18, 2020 2:25 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: OOBOL and English was Re: Still COBOL After All These Years? This reminds me of a very old story (begin of 1990s). I once had to write a translator for a report generator language (not RPG, but similar), which was in use on Polish ODRA computers (ICL clone). The target language was COBOL. After some weeks of work, I delivered the first version. The "customers" (a team of programmers of another company) tested it and after some days responded like this: "very fine, very fine. BTW: is it possible that the subtractions all show the wrong sign?" It turned out that I generated SUBTRACT A FROM B GIVING C for C := A - B much the same way as ADD A TO B GIVING C for C := A + B ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
