#!/bin/sh
tmp=${TMPDIR-/usr/tmp}/plot.$$
trap 'rm "$tmp"; exit' 0 1 2 3 15
< ${1-assn2.grades} awk '
{
	if ($1 in grade) {
		print "Duplicate grade for " $1 | "cat >&2"
		exit 1
	}
	if ($2 > 100 || $2 < 0) {
		print "Illegal grade for " $1 " of " $2 | "cat >&2"
		exit 1
	}
	grade[$1] = $2
}
END {
	for (student in grade) {
		slot = int(grade[student] / 10);
		if (slot == 10) slot = 9;
		bar[slot]++;
	}
	for (slot = 0; slot < 10; slot++) {
		print 0+bar[slot];
	}
}' > "$tmp"
case $? in
0)	;;
*)	exit;;
esac
gnuplot << EOF
set terminal pbm
set output "grade.plot.ppm"
plot "$tmp" with boxes
quit
EOF
ppmtogif < grade.plot.ppm > grade.plot.gif