running time of binary search

[aminhimo]

which has better running time recursive or iterative binary search?

[ialbluwi]

Recursive implementations, in general, are more expensive than iterative implementations for the same algorithm. However, binary search does a very small number of comparisons, which might make the difference between the two versions insignificant. You can try it yourself. Call each version a large number of times and measure the time and see if the difference is noticeable or not.