proc expand-calculate new variables

[Ronein]

Hello

I want to ask please what exactly this transformation do?

convert X=Cum_X/transformout=(cusum 5);

I am trying to understand the calculation but didn't understand the calculated values.

May anyone help please to understand the calculation of the cumulative sum?

data have;
input  X;
cards;
0
3
0
1
0
0
5
0
0
0
1
1
2
;
run;


proc expand data=have out=want method=none;
convert X=Cum_X/transformout=(cusum 5);
Run;

e 

[PaigeMiller]

Show us the output you get. Explain exactly what parts of the output you do not understand.