What is the fastest way to get array cell number?

Question

Programming

There is an array of type:
{122,13523,2123,2,4,125,5600,334..n}
What is the fastest way to get a cell in which the value is 4?
Moreover, the standard option is also considered - a cycle.

Answer 1

If the array is not sorted (and in general, nothing is known about it) - linear search.
If sorted - binary search.