Difference between successive rows in a column

I have a table with 60 columns and 60,000 rows. I want to find the difference of second row and first row of 40th column, then difference between 3rd and 2nd row, 4th and 3rd row, etc. It goes until it reaches he last row. Also, I need to assign those difference values in the 61st column. Please help me with this.

Answer 1

[Fangjun Jiang]

a=magic(6);
b=diff(a(:,4))

b = 5×1

-5 1 -5 -5 1

a(2:end,end+1)=b

a = 6×7

35 1 6 26 19 24 0 3 32 7 21 23 25 -5 31 9 2 22 27 20 1 8 28 33 17 10 15 -5 30 5 34 12 14 16 -5 4 36 29 13 18 11 1