Data step flow

[shengnian]

I am learning SAS data setp flow recently, and I found a interesting question. Please see the following programs. The only difference between data bb and data cc is that " put _all_" was a comment statement in data bb, which  was not in data cc.

However, it made a big difference to the result. I could underatand the number of dataset bb is zero, but I wonder what happened to dataset cc.  Can someone explain it?  Thanks!

data aa;
do A = 1 to 20;
output;
B = A;
end;
run;

data bb;
do until (i >= 5);
set aa;
/* put _all_*/
i = _N_;
i + 1;
end;
run;

data cc;
do until (i >= 5);
set aa;
put _all_
i = _N_;
i + 1;
end;
run;

[ballardw · Accepted solution]

If the code you ran is exactly as posted you get a difference because the Put _all_ does not have a ; at the end and the next line i=_n_ is considered part of the PUT instruction.

[shengnian]

You are right, I have noticed it yet. Thanks very much! 

[PGStats]

@shengnian, please mark @ballardw's answer as Accepted.

[shengnian]

Thanks for your remainding!