Code Example
A C function that implements the XOR swap algorithm:
void xorSwap (int *x, int *y) { if (x != y) { *x ^= *y; *y ^= *x; *x ^= *y; } }Note that the code does not swap the integers passed immediately, but first checks if their addresses are distinct. This is because, if the addresses are equal, the algorithm will fold to a triple *x ^= *x resulting in zero.
The body of this function is sometimes seen incorrectly shortened to if (x != y) *x^=*y^=*x^=*y;. This code has undefined behavior, since it modifies the lvalue *x twice without an intervening sequence point.
Read more about this topic: XOR Swap Algorithm
Famous quotes containing the word code:
“Faultless honesty is a sine qua non of business life. Not alone the honesty according to the moral code and the Bible. When I speak of honesty I refer to the small, hidden, evasive meannesses of our natures. I speak of the honesty of ourselves to ourselves.”
—Alice Foote MacDougall (1867–1945)
“Hollywood keeps before its child audiences a string of glorified young heroes, everyone of whom is an unhesitating and violent Anarchist. His one answer to everything that annoys him or disparages his country or his parents or his young lady or his personal code of manly conduct is to give the offender a “sock” in the jaw.... My observation leads me to believe that it is not the virtuous people who are good at socking jaws.”
—George Bernard Shaw (1856–1950)