What does it mean when an array name is in parentheses with a caret pointer before it?

Question

I have an array of unsigned numbers, called dataArray (actually in the program I am trying to figure out, they are entered as hexadecimal numbers, but I don't think that's important). I have another variable of type unsigned char, called c.

What does this do?

unsigned int dataArray[]={1,2,3,4,5};
unsigned char c;
x=c^ (dataArray)[i];

I have read that the caret is a reference to c, but what does it mean when the array name is in parentheses? It seems that x is just set to the (i-1)th element in dataArray, but under what conditions is that not so?

Thanks.

Answer 1

The parenthesis don't impact the semantics here. x is computed as the bitwise exclusive-or of c (undefined here) and dataArray[i].

Answer 2

If this is really C++, then the '^' is the XOR bitwise operator. The parentheses are extra and do nothing in this example.

Answer 3

The ^ character as it is used here is a bitwise XOR (see wikipedia). The parentheses don't to anything here, as the operator [] has higher precedence than bitwise-xor.

Answer 4

The ^ is not overloaded, as far as I know. If it is entered and compiles properly, it is going to attempt a XOR operation, though in this case it's probably going to be messing with data you don't want it to...

Answer 5

Ok, cool. That makes sense in the program I'm using. I had thought the caret was a pointer, but it's an XOR and then later on in the line there's an & (bitwise AND). The program is for sending and receiving signals from electronics, so bit-level logic is to be expected. Thanks very much for the fast replies.

Answer 6

In some derived language, the caret is used to declare a managed pointer. It's the so-called C++/CLI language made by microsoft and is used in .Net. It doesn't have that meaning in normal C++. In expressions, the caret means, as already explained by others, the bit-wise XOR, anyway.