Shift and division: Bit right/left shift to implement arithmetic division and multiplication by a power of 2. It works with unsigned types, and signed types for left shift. Division with signed types rounds toward 0, but right shift rounds to negative infinite.

int a, b, c;

a = -1;

b = a >> 1; // b is -1;

c = a / 2; // c is 0;

if (x < 0) x = -x;

// assume x is always positive

// but is it wrong

A shift by more than BITS_PER_LONG-1 is undefined by the C-standard.

int foo (int k)

{

int t = ABC >> (BIT_PER_INT - k);

return t; // when k == 0, undefined

}

if (k == 0) t = 0; // add this before return in foo

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