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Old 05-07-2005, 04:53 AM   #1
ar1
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Question Interesting C Question


Take a look at the following code:

Code:
char a[10] = "abcdefghi";
printf("%s", a[3]);
printf("%s", 3[a]);
Both the printf's give the same output. Why??

It must be something to do with the way the string is represented in the memory by the C compiler, but what is it?

I would have thought that the offset is multiplied by the size of char, in which case they should give different outputs :/
 
Old 05-07-2005, 05:47 AM   #2
nukkel
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Re: Interesting C Question

Yes this is quite cool...

In C,
Code:
x[\i]
is equivalent to
Code:
*(x + i)
, and because of the commutativity (is this the right word in English???) of the addition this is also equivalent to
Code:
*(i + x)
which in turn can also be written as
Code:
i[x]
...

Quote:
Originally posted by ar1
I would have thought that the offset is multiplied by the size of char, in which case they should give different outputs :/ [/B]
sizeof (char) = 1, so that makes no difference here.

greets,
nukkel
 
Old 05-07-2005, 10:24 AM   #3
jtshaw
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The size of the type actually shouldn't matter in this case. Pointers in C are always the same size, regardless of the datatype they are pointing too.
 
  


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