labview

Hi,

             Cand you suggest how to implement the below functionality . I have a 1dimentional array. I want to search a number in array which is not present but i want to knw the index of the number where it lies in between. For example array contains 1, 2, 4 , 5 and i need to find element 3 , which is not present. But it lies between 2 and 4 . So i want to get the index of number 2 and 4. 

Thanks

Vikas