average:
	proc options (main);
	/* grade averaging program */

	dcl
		sysin file,
		(grade,total,n) fixed;

	on error (1)
		/* conversion */
		begin;
		put skip list('Bad Value, Try Again.');
		get skip;
		go to retry;
		end;

	on endfile (sysin)
		begin;
		if n ^= 0 then
			put skip list
				('Average is',total/n);
		stop;
		end;

	put skip list
		('Type a List of Grades, End with Ctl-Z');
	total = 0;
	n = 0;

	retry:
	put skip;
		do while('1'b);
		get list (grade);
		total = total + grade;
		n = n + 1;
		end;
	end average;