Explained

What is x - 1 wrt x x - 1 is derived from x by flipping all bits to the right of (and including) the rightmost set bit (1) in x to 0s. Examples x = 4 (100 in binary), x - 1 = 3 (011 in binary). x = 6 (110 in binary), x - 1 = 5 (101 in binary). What is X & (x-1)? x & (x - 1) results in a value with all bits from x remaining the same except for the rightmost set bit (1), which becomes 0. ...