Re: Compiler bug? Two variables of same name in one scope

From:

Jonathan Leffler <jleffler@earthlink.net>

Newsgroups:

comp.lang.c++.moderated

Date:

Tue, 30 Oct 2007 13:47:43 CST

Message-ID:

<13ieb1j5eej8f40@corp.supernews.com>

Rune Allnor wrote:

[...] It turned out that I had renamed a
variable to a name that was already in use in the relevant
scope.

Strictly, no - the inner declaration is in a new scope.

Basically, the situation was as in this function:

double f(double a)
{
   if(1)
   {
       double a = a; // <------------- This actually compiles...
   }
   return a;
}

The variable name was already used in the argument to
the function, and I had inadvertedly used the same name
for a variable inside an if-block. As in the example above,
I used the parameter version of the variable to initialize
the local version.

What surprised me after I found the cause of the bug
was that the compiler actually accepted that piece
of code without complaints. Is that a bug in my compiler
or is the above legal C++ code?

Perfectly legal in both C++ and C.

What wouldn't work is:

int f(int i)
{
    int i = i;
}

--
Jonathan Leffler #include <disclaimer.h>
Email: jleffler@earthlink.net, jleffler@us.ibm.com
Guardian of DBD::Informix v2007.0914 -- http://dbi.perl.org/

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