Why these many observations are created in the following program? - sas

Question

data test;
infile cards dsd dlm=', .';
input stmt : $ ##;
cards;
T
;run;
/*-----------------------------------------------*/
data test;
infile cards dsd dlm=', .';
input stmt : $ ##;
cards;
Th
;run;
/*-----------------------------------------------*/
data test;
infile cards dsd dlm=', .';
input stmt : $ ##;
cards;
This is SAS.
;run;
When first program is run, 80 observations are created
When second program is run, 79 observations are created
When third program is run, 72 observations are created
I know these program has worst programming style. Wrong options are set for wrong technique. DSD option is set, double trailing operator ## (line holder), Colon modifier (:) are used and more than 1 delimeter is used which is worst SAS programming ever.
Aside from this I want to know why so many observations are created, why 80? 79? how program is executed? I think DSD option & 2 delimeters have major impact. Can anyone explain?

Answer 1

The reason you get more records than you expect is because CARDS are fixed length records. The reason you get a difference number of records is because there is a different number of null fields left after reading the non-null field(s). You can see this by adding the COL option to the INFILE statement to show you where the column pointer is after reading each field. Col=3, 4 , 13
data test;
infile cards dsd dlm=', .' col=c;
input stmt : $ ##;
col=c;
cards;
T
;run;
proc print data=test(obs=5);
/*-----------------------------------------------*/
data test;
infile cards dsd dlm=', .' col=c;
input stmt : $ ##;
col=c;
cards;
Th
;run;
proc print data=test(obs=5);
/*-----------------------------------------------*/
data test;
infile cards dsd dlm=', .' col=c;
input stmt : $ ##;
col=c;
cards;
This is SAS.
;run;
proc print data=test(obs=5);
run;