How to unset a specific bit in an integer

Question

Say, I have a integer like 10101, I would like to unset the third bit to get 10001; if I have 10001, I will still get 10001; how can I achieve it?

unset(int i, int j)
int i= 10101 or 10000
int j = 00100

Answer 1

Assuming that you are indexing bits from the right, this should work to unset a particular bit in value:

int mask = 1 << bitIndex;
value &= ~mask;

You can set the bit using similar code:

value |= mask;

where mask is as before. (This assumes that bit indexing starts at 0.)