Check whether the number has only first and last bits set | function to check whether ' n ' is a power of 2 or not ; function to check whether the number has only first and last bits set ; Driver program to test above
function powerOfTwo ( n ) { return ( ! ( n & n - 1 ) ) ; } function onlyFirstAndLastAreSet ( n ) { if ( n == 1 ) return true ; if ( n == 2 ) return false ; return powerOfTwo ( n - 1 ) ; } var n = 9 ; if ( onlyFirstAndLastAreSet ( n ) ) document . write ( " " ) ; else document . write ( " " ) ;