bagpiper@pnet02.gryphon.com (Michael Hunter) (11/09/89)
gateley@m2.csc.ti.com (John Gateley) writes: >I probably shouldn't do this, but here are some nitpicks: >Ada is NOT a much more powerful language than C. Ada has some features >that C doesn't, and C has some features that Ada doesn't and so on. >They are both turing complete (or whatever the phrase is). If you >are going to make such a broad statement, you need to carefully >define what powerful is. Yea...I could write a turing machine in either....in fact you can write a turing machine with gotos, moves, and compares. I don't think I would even be happy with this machine. Mike Hunter - Box's and CPU's from HELL: iapx80[012]86, PR1ME 50 Series, 1750a UUCP: {ames!elroy, <routing site>}!gryphon!pnet02!bagpiper INET: bagpiper@pnet02.gryphon.com
bs@alice.UUCP (Bjarne Stroustrup) (11/14/89)
Since C++ has been mentioned several times in the discussions here (comp.lang.ada) lately it might be appropriate for me to comment. In my opinion, the most significant difference between C++ and Ada is that you don't have to use C++. If you don't like it, no government will try to bribe or coerce you into using it. I do understand that governments sometimes have to operate in this manner. However, if you don't like C++, don't use it - but please first try to make sure you know what you are rejecting (and why) and realize that other people will have different requirements and tastes than you and may therefore decide differently. Whatever support C++ has it has earned. Note that you have never seen an AT&T ad for C++. Even if you don't like C++, if you are prevented from using it, or if C++ simply isn't the right choice for you now you might still learn something from it. Ada afficionados often dismiss C++ for not being standardized. That is a major issue to some because in some areas ANSI and/or ISO standardization is a legal or semi-legal requirement for use of a language. Just don't use C++ in those areas. Critizising C++ for not being standardized is a bit like critisizing a person for being young. Sometimes youth is a disqualifying factor, sometimes it isn't. Anyway, most C++ standardization problems arise because C++ has several independent implementations. This is a problem of succcess; most languages never get a second implementation: their application areas and user base simply never grows to make a second (or a tenths) implementation viable. For many people, the implementations are not sufficiently different for the largely accidental incompatibilities to be a really major problem and the implementations are getting less different as the compiler writers are cooperating to create a genuine standard. Formal ANSI standardization has started. People for whom the current state of affairs is unacceptable can wait and look again in a couple of years to see if they like C++ better then. Some critisisms have been leveled at C++ on comp.lang.ada that ought not to have been. Some were based on the assumption that C++ is simply a minor variation of C and refered to point about C that simply didn't hold for C++. Similarly, some people have managed to confuse C++ and Smalltalk. Please read some technical information about C++ yourself instead of relying on heresay or hype merchants. There is a large and vigorous C++ litterature. The last half-way comprehensive bibliography is 11 typeset pages. I can recommend a paper (by myself,sorry): ``What is Object-Oriented Programming?'' May'88 IEEE Software magazine. some books: 0-07-881522-3 Using C++ Eckel 0-13-723156-3 Programming in C++ Dewhurst & Stark 0-201-11497-6 C++ Answer Book Tony Hansen 0-201-12078-X C++ Programming Language Bjarne Stroustrup 0-201-16487-6 C++ Primer Lippman some proceedings (usenix: 213-592-1381): Proc USENIX C++ workshop, Santa Fe, NM, Nov'87 Proc USENIX C++ Conference, Denver, CO, Oct'88 and the AT&T 2.0 documentation (AT&T: 1-800-432-6600 or 317-352-8557): reference manual: 307-146 library manual: 307-145 selected readings: 307-144 release notes: 307-090 Relative to Ada, I think that C++'s major deficiencies are the lack of an exception handling mechanism and of a mechanism providing generics (see the ``whatis paper'' or my book). Proposals for remedying this can be found in: B. Stroustrup: Parameterized Types for C++. Journal of Object-oriented Programming. Jan/Feb 1989 and the 2nd USENIX proceedings. A. Koenig and B. Stroustrup: Exception Handling for C++. Proc. C++ at Work Conference. Nov'89. The absense of generics is usually (incompletely) compensated for through the use of combinations of inheritance and macros. The absense of exceptions is usually (incompletely) compensated for through various uses of pointers to functions. I do not consider C++'s lack of direct support for concurrency a weakness. On the contrary, concurrency supported through libraries can serve a wider range of needs better. Unfortunately, I see no way of proving this conjecture in general.