templates4/postfix2.scala
changeset 288 65731df141a5
parent 220 3020f8c76baa
--- a/templates4/postfix2.scala	Wed Oct 30 12:47:10 2019 +0000
+++ b/templates4/postfix2.scala	Wed Oct 30 14:07:58 2019 +0000
@@ -2,6 +2,9 @@
 // including Associativity for Operators 
 // =====================================
 
+object CW9b {
+
+
 // type of tokens
 type Toks = List[String]
 
@@ -32,7 +35,7 @@
 // the operations in the basic version of the algorithm
 val ops = List("+", "-", "*", "/", "^")
 
-// (8) Implement the extended version of the shunting yard algorithm.
+// (3) Implement the extended version of the shunting yard algorithm.
 // This version should properly account for the fact that the power 
 // operation is right-associative. Apart from the extension to include
 // the power operation, you can make the same assumptions as in 
@@ -45,7 +48,7 @@
 // syard(split("3 + 4 * 8 / ( 5 - 1 ) ^ 2 ^ 3"))  // 3 4 8 * 5 1 - 2 3 ^ ^ / +
 
 
-// (9) Implement a compute function that produces a Long(!) for an
+// (4) Implement a compute function that produces a Long(!) for an
 // input list of tokens in postfix notation.
 
 //def compute(toks: Toks, st: List[Long] = Nil) : Long = ...
@@ -63,3 +66,4 @@
 // compute(syard(split("( 4 ^ 3 ) ^ 2")))  // 4096
 // compute(syard(split("( 3 + 1 ) ^ 2 ^ 3")))   // 65536
 
+}