Q. Subsequent statements set every element of matrix?

Let a= [2,4,6,8,10], b=[1,3,5,7,9], c=[0,0,0,0,0]

Consider the subsequent program section

FORALL (i = 2:4)

  a(i) = a(i-1)+a(i+1)

  c(i) = b(i) *a(i+1).

END FORALL

The calculations would be:

   a[2] =a[1]+a[3] =2+6=8

   a[3] =a[2]+a[4] =4+8=12

   a[4] =a[3]+a[5] = 6+10=16

   c[2] = b[2] *a[3] = 3*12=36

   c[3] = b[3] *a[4] = 5*16=80

   c[4] = b[4] *a[5] =7*10=70

So output is

a= [2,8,12,16,10], b=[1,3,5,7,9], c=[0,36,80,70,0]