n00b question

Is there a way to declare an array in C so the indexing starts at something besides zero?  Like if I wanted the array to be a[-10] to a[10] instead of a[0] to a[20]?

I want an array that holds a number for each point in a 2D grid, but I want the origin (point (0,0)) to be in the middle, so I want to use negative indicies.

n/m though, I figured out how to do it with a #define.