I would consider using a format (e.g. infbest.) to display infinities:

proc format;
value infbest(DEFAULT=32 FUZZ=0 MULTILABEL NOTSORTED)
.I = "+Infinity"
.M = "-Infinity"
._ - .Z = "Missing"
other = [best32.]
;
run;

data test;
input a b;
format c infbest.;
c = divide(a,b);
cards;
1 0
1 1
-1 0
. 1
. .
. 0
1 .
0 .
-1 .
1 2
-1 3
0 4
;
run;

proc print;
run;