Arduino and Bitwise, unexpected result

Question

Getting my self a bit confused here.

I would like to test if a set of bits (3 bits) contains a bit in a certain postion.

if (B110 & B010 == B010)

(B110 being the number to check, B010 the bit I want to see if is there)

The above code isn't giving me the expected out come, both B110 is true and B101 is true. I am pretty sure that I need to use a &(and) to test with the mask B010.

My understanding is that B110 & B010 would be equal to B010 and that B101 & B010 would equal B000. But my if statement is run with both test bits?

I am coding in an Arduino, I'm sure that it's a simple misunderstanding on my behalf but not sure where.

Answer 1

Try if ((B110 & B010) == B010)

At the moment it's running as if (B110 & (B010 == B010)) which will always be true.

As this table shows, == and != have a higher precedence than &, | etc.

Answer 2

The "== B010" is actually unnecessary in this test. In C, 0 represents "false," while any nonzero value is considered "true." B110 & B010 (or any other value with that bit set) will return B010, which is not equal to 0, so the test succeeds.