algorithm - The behavior of the Mathf.RoundToInt()

Question

I have a question about the Mathf.RoundToInt()

int val = Mathf.RoundToInt(10.5f);
val = Mathf.RoundToInt(9.5f);
val = Mathf.RoundToInt(8.5f);

The above generates "10, 10, 8" not "11, 10, 9".

According to the reference manual of Unity, Mathf.RoundToInt() returns "even value" when the 1st decimal place is "5" (e.g. 8.5 -> 8.0).

I would like to know the reason why the Mathf.RoundToInto() return like this, not like normal rounding (e.g. 8.5 ->9.0, 9.5 -> 10.0).

Answer 1

来自http://en.wikipedia.org/wiki/Rounding#Round_half_to_even：

对于 [...] 值的合理分布，四舍五入数字的预期（平均值）与原始数字的预期（平均值）相同。