[1117] in java-interest
Re: Assertions in Java (& more)
daemon@ATHENA.MIT.EDU (jim frost)
Sat Aug 19 02:05:37 1995
To: John Barton <jjb@watson.ibm.com>
Cc: "John D. Mitchell" <johnm@CSUA.Berkeley.EDU>, anders@in.otc.com.au,
java-interest@java.sun.com
In-Reply-To: Your message of "Fri, 18 Aug 1995 15:24:39 EDT."
<9508181924.AA116973@jjb.watson.ibm.com>
Date: Fri, 18 Aug 1995 16:13:51 -0400
From: jim frost <jimf@world.std.com>
|jim frost writes:
|[comments on base-class name hiding in C++, then:]
|
|>A related, but far more serious and subtle, problem is accidentally
|>overloading a virtual member function rather than overriding it:
|>
|> class Foo {
|> public:
|> virtual void Add(unsigned int);
|> };
|>
|> class Bar : public Foo {
|> public:
|> void Add(int);
|> };
|>
|>The omission of "unsigned" hides Foo::Add(unsigned int). At best you
|>*might* get a signed/unsigned mismatch conflict from the compiler when
|>Bar::Add() is called -- but probably not. What I have gotten in cases
|>like this is some very hard-to-find bugs.
|
|My C++ compiler says:
| "Bar::Add(int)" hides the virtual function "Foo::Add(unsigned int)".
|so perhaps you are using an old compiler, one developed before Java
|even existed. Compare Java to C++ using today's technology. Java still
|has plenty of interesting potential without any need to spread false
|rumors about C++.
I'm glad to hear that some compilers are sane about this kind of
thing. FWIW, I'm using both SGI's C++ compiler (the one that shipped
with IRIX 5.3, ie less than six months old) and MSVC++ 2.0 (roughly
two years old).
Regardless, those examples illustrate a couple of the surprises people
really see with C++.
jim frost
jimf@world.std.com
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