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I would like to set the i-th bit to zero no matter what the i-th bit is.
unsigned char pt = 0b01100001; pt[0] = 0; // its not how we do this... Setting it to one, we can use a mask pt | (1 << i) but i'm not sure how to create a mask for setting 0, if thats possible.
You just have to replace the logical OR with a logical AND operation. You would use the & operator for that:
pt = pt & ~(1 << i); You have to invert your mask because logical ANDing with a 1 will maintain the bit while 0 will clear it... so you'd need to specify a 0 in the location that you want to clear. Specifically, doing 1 << i will give you a mask that is 000...010..000 where the 1 is in the bit position that you want, and inverting this will give 111...101...111. Logical ANDing with this will clear the bit that you want.
You could stick with this:
// Set bit at position `bitpos` in `pt` to `bitval` unsigned char bitpos = 1; unsigned char pt = 0b01100001; bool bitval = 1; // Clear the bit pt &= ~(1u << bitpos); // Set the bit pt |= (bitval << bitpos);