How can I safely average two unsigned ints in C++?

Question

Using integer math alone, I\'d like to \"safely\" average two unsigned ints in C++.

What I mean by \"safely\" is avoiding overflows (and anything else that can be th

Answer 1

Your method is not correct if both numbers are odd eg 5 and 7, average is 6 but your method #3 returns 5.

Try this:

average = (a>>1) + (b>>1) + (a & b & 1)

with math operators only:

average = a/2 + b/2 + (a%2) * (b%2)