%macro analyst(inputfile);
data a;
infile "/home/grego1/STAT 540/&inputfile..txt";
input y x;
run;
proc sort data=a out=unique nodupkey; by x;
run;

/* Find the number of levels of X             */
data _null_; set unique end=last;
if last=1 then  call symputx("XLevels",_n_); 
run;

/* Compute a t-test for X with 2 levels         */
%if &XLevels = 2 %then %do;
proc ttest data=a; class x;
var y; run;
%end;
/* ANOVA if X has more than 2 levels           */
%else %if &Xlevels>2 %then %do;
proc glm data=a;
class x; model y=x; run;
%end;
/* No analysis when X has 1 level               */
%else %do;
proc univariate normal data=a;
histogram y;
var y;
proc print data=a;
footnote "No testing; X variable has only one level"; run; %end;
%mend;


%analyst(IFMacro2)
%analyst(IFMacro4)
%analyst(IFMacro1)