Editing XOR swap algorithm (section)

==Code example==
A [[C (programming language)|C]] function that implements the XOR swap algorithm:
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<syntaxhighlight lang="c">
void XorSwap(int *x, int *y) 
{
  if (x == y) return;
  *x ^= *y;
  *y ^= *x;
  *x ^= *y;
}
</syntaxhighlight>
The code first checks if the addresses are distinct and uses a [[Guard (computer science)#Flatter code with less nesting|guard clause]] to exit the function early if they are equal. Without that check, if they were equal, the algorithm would fold to a triple <code>*x ^= *x</code> resulting in zero.

The XOR swap algorithm can also be defined with a macro:
<syntaxhighlight lang="c">
#define XORSWAP_UNSAFE(a, b)                                                   \
  ((a) ^= (b), (b) ^= (a),                                                     \
   (a) ^= (b)) /* Doesn't work when a and b are the same object - assigns zero \
                  (0) to the object in that case */
#define XORSWAP(a, b)                                                         \
  ((&(a) == &(b)) ? (a) /* Check for distinct addresses */                    \
                  : XORSWAP_UNSAFE(a, b))
</syntaxhighlight>