Cumulative sum function of daily rainfall

I have a large daily rainfall data and require to create a new series with rainfall of 1, 2 , 3 and 4 day will be same as observed, then day 5 rainfall will be sum of 1, 2,3, 4 and 5 day rainfall. 6 day rainfall will be sum of rainfall of 2, 3, 4, 5 and 6 day rainfall. Repeat this function for 50 years daily rainfall data. Could any body suggest me matlab script for this kind of analysis? data file will be like this

date      rainfall   Cumulative rainfall
1/1/1950  10                10
1/2/1950  0                  0
1/3/1950  0                  0
1/4/1950  0                  0
1/5/1950  15                 25
1/6/1950   5                 20
1/7/1950   10                35
1/8/1950   7                 42
.........

Answer 1

[Walter Roberson]

conv() the rainfall data with one(1,5)

[Saleem Sarwar]

Thanks Walter. This function has not solved my problem fully. The output is like that

Rainfall  Cumulative after using Conv function  Remarks
37  84  1st three days
41  126  1 to 4 days
6  155  1 to 5 days
42  123  2 to 6 days
29  95  3 to 7 days
5  114  4 to 8 days

I require following output

Rainfall  Cumulative after using Conv function  Remarks
37  37  1st day
41  41  2nd day
6  6  3rd day
42  126  4 day
29  155  1 to 5 days
5  123  2 to 6 days

Thanks

[Walter Roberson]

If you let the rainfall be stored in the column vector r, then

cr = cumsum([0;r]);
col2 = [r(1:4);ss(6:end)-ss(1:end-5)];
[r,col2]

Or

col2 = [r(1:4); conv(r, ones(1,5), 'valid')];  %one step
[r,col2]