How can I sum row element to the end?

I have this matrix "a" and it size is changeable and I need to sum all elements then I the sum from the second elements to the end than the third element to the end and so on

I tired this for loop but does not

a=[2; 3; 8; 2];
[row,column]=size(a);

   for i=1:row
      y=sum (a(i,1),end) ;
       tt(i,1)=y;
   end
   tt

The code I want it to work if I change the matrix "a" size

Answer 1

[Walter Roberson]

sum(a)-[0;cumsum(a(1:end-1))]