Changing bits in an int in C?

Question

So I have a 16 bit number. Say that the variable name for it is Bits. I want to make it so that Bits[2:0] = 001, 100, and 000, without changing anything else. I'm not sure how to do it, because all I can think of is ORing the bit I want to be a 1 with 1, but I'm not sure how to clear the other bits so that they're 0. If anyone has advice, I'd appreciate it. Thanks!

Answer 1

To clear certain bits, & with the inverse of the bits to be cleared. Then you can | in the bits you want.

In this case, you want to zero out the lower three bits (111 in binary or 7 in decimal), so we & with ~7 to clear those bits.

Bits = (Bits & ~7) | 1; // set lower three bits of Bits to 001