A 64-bit integer can be viewed as an array of 64 bits, with the bit at index 0 corresponding to the least significant bit and the bit at index 63 corresponding to the most significant bit. For above problem, we have flip ith bit, i.e if ith bit is 0 then we have to change it to 1, and vice versa. For this, take a long integer 1, move it to ith position by left sifting, then xor with number.
<?php $a = 134 ; // original number $i = 3 ; //four bit index from zero $b = $a ^ (1 << $i ); printf("Original number : %b" , $a) ; printf(" After of %d bit number : %b" , $i, $b) ;
Original number : 10000110 After of 3 bit number : 10001110