yoshi@erdos:~/Main/www/2006ii/mac122a/exx
$ prog5.4 "+ 2 3"
5
yoshi@erdos:~/Main/www/2006ii/mac122a/exx
$ prog5.4 "* + 2 3 * 2 4"
40
yoshi@erdos:~/Main/www/2006ii/mac122a/exx
$ prog5.4 "* + 7 * * 4 6 + 8 9 5"
2075
yoshi@erdos:~/Main/www/2006ii/mac122a/exx
$