Re: equality operator question

Jack Klein wrote:
> On Sun, 4 May 2008 22:40:28 -0400, "barcaroller"
> <barcaroller@[EMAIL PROTECTED]
> wrote in comp.lang.c++:
>
>> Is it now common practice to use conditional statements like
>>
>>     if (0    == i)
>>     if (-1   == i)
>>     if (true == i)
>>     if (5    == i)
>>
>> over the more traditional statements like
>>
>>     if (i ==    0)
>>     if (i ==   -1)
>>     if (i == true)
>>     if (i ==    5)
>>
>> for all types of 'i' (PODs and cl*****)?
>
> The reason for writing the constant first in an equality comparison is
> quite simple.  A fairly common typographical error is type only one
> '=' once in a while when two are intended, and needed.
>
> Consider the implications of accidentally typing:
>
>   if (i = 0)
>
> ...when you meant to type:
>
>   if (i == 0)
>
> Assuming a built-in type, or even a class type having an assignment
> operator accepting an int, then the first version, the type, is not
> only always false, but it also destroys the existing value of 'i'. Yet
> it is syntactically correct and swallowed by the compiler without
> complaint.
>
> On the other hand, if you accidentally type "if (0 = i), the compiler
> will emit a diagnostic and reject it.
>
> So it is a very inexpensive method of catching a typing error on the
> very first compile.  This is not an extremely common error, but is one
> which happens to everyone once in a while.  And of course it doesn't
> help when you are comparing two objects, but comparisons with a
> constant are fairly frequent.
>
> Some programmers consider it hideously ugly and refuse to ever use it.
> I think it is useful and I use it.  It works, and it saves time when
> you do happen to make that typo.

I agree, but my compiler warns me if an assignment is being made inside an

if statement.  Otherwise I probably would use that format.  But since it 
does, I stick with the more traditional if ( variable == value )

-- 
Jim Langston
tazmaster@[EMAIL PROTECTED]