Check if one of the numbers is one 's complement of the other | function to check if all the bits are set or not in the binary representation of ' n ' ; all bits are not set ; if true , then all bits are set ; else all bits are not set ; function to check if one of the two numbers is one 's complement  of the other ; Driver code
function areAllBitsSet ( n ) { if ( n == 0 ) return false ; if ( ( ( n + 1 ) & n ) == 0 ) return true ; return false ; } function isOnesComplementOfOther ( a , b ) { return areAllBitsSet ( a ^ b ) ; } let a = 10 , b = 5 ; if ( isOnesComplementOfOther ( a , b ) ) document . write ( " " ) ; else document . write ( " " ) ;