I'm immensely indebted to all for comments and suggestion. I should explain why I intend to learn macros. I wrote programs in MATLAB. But statistics there is very poor. Also , because my university buy SAS licence I decided to quit writing codes in MATLAB and I choose SAS. In SAS I would like to write my own code, as well - e.g. simulation (Monte Carlo). But I noticed that SAS does not allow to write code like this:

do i=1 to 1000; proc something; ....... run; proc something; ....... proc something; ....... run; run; end; It is immposible to nested proc, data and so on.

I bought book: SAS for Monte Carlo Studies (Fan, Felsovalyi, Silvo, Keenan). But there are only macros.I tried to modify code to simulate 2 variables X and Y from independent normal pdf. Next I count Pearson's correlation. But I can't to figure out how to repeat this 200 times to get 200 Pearson's correl. Therefore I thought that I should learn macro. Does anybody know how to do it. Program is (it's a pity that I can't write: repeat 200 my program end;)

DATA DAT; DO I=1 TO 1000; X=RANNOR(0); Y=RANNOR(0); OUTPUT; END; *** use PROC CORR to get Pearson r, results as SAS dataset PEARSON; PROC CORR DATA=DAT NOPRINT OUTP=PEARSON; VAR X Y; RUN; DATA PEARSON; SET PEARSON; IF _NAME_='X'; CORR=Y; KEEP CORR; run;

Thank you vary much Rob