Implement the body of the following function using a binary search of
the array. You do not need to check the precondition.
public static boolean has42(int[ ] data, int start, int end)
// Precondition: The elements data[start]...data[end] are sorted from smallest
// to largest. This array segment might be empty (indicated by end being less
// than start).
// Postcondition: A true return value indicates that the number 42 appears in
// data[start]...data[end]. A false return value indicates that 42 doesn’t