Counting No. of values in Arrays

I define an array of 10 items, say a[10].
I give for 3 arrays say a[0] = 38, a[3] = 980, a[7] = 98
The remaining arrays 7 of them are without values.
What I want is to get the count of number of arrays (with values) and in this case should give the count as 3.

Is there any function /user defined logic to do this one.
Anticipating a postive response from your end for this case.
Thankyou in advance for your help.