If x is greater than arr [ mid ] , then either arr [ mid + 1 ] is ceiling of x or ceiling lies in arr [ mid + 1. . . high ]
if ( $ arr [ $ mid ] < $ x ) return findCrossOver ( $ arr , $ mid + 1 , $ high , $ x ) ; return findCrossOver ( $ arr , $ low , $ mid - 1 , $ x ) ; }