diff -r c02929f2647c -r 6e1237691307 pre_marking3/postfix_test2.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pre_marking3/postfix_test2.scala	Fri Jan 15 02:40:57 2021 +0000
@@ -0,0 +1,8 @@
+import CW9a._
+
+assert(compute(syard(split("3 + 4 * ( 2 - 1 )"))) == 7)
+assert(compute(syard(split("10 + 12 * 33"))) == 406)
+assert(compute(syard(split("( 5 + 7 ) * 2"))) == 24)
+assert(compute(syard(split("5 + 7 / 2"))) == 8)
+assert(compute(syard(split("5 * 7 / 2"))) == 17)
+assert(compute(syard(split("9 + 24 / ( 7 - 3 )"))) == 15)