tasks a-s

Task/Parsing-RPN-calculator-algorithm/Go/parsing-rpn-calculator-algorithm.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+    "fmt"
+    "math"
+    "strconv"
+    "strings"
+)
+
+var input = "3 4 2 * 1 5 - 2 3 ^ ^ / +"
+
+func main() {
+    fmt.Printf("For postfix %q\n", input)
+    fmt.Println("\nToken            Action            Stack")
+    var stack []float64
+    for _, tok := range strings.Fields(input) {
+        action := "Apply op to top of stack"
+        switch tok {
+        case "+":
+            stack[len(stack)-2] += stack[len(stack)-1]
+            stack = stack[:len(stack)-1]
+        case "-":
+            stack[len(stack)-2] -= stack[len(stack)-1]
+            stack = stack[:len(stack)-1]
+        case "*":
+            stack[len(stack)-2] *= stack[len(stack)-1]
+            stack = stack[:len(stack)-1]
+        case "/":
+            stack[len(stack)-2] /= stack[len(stack)-1]
+            stack = stack[:len(stack)-1]
+        case "^":
+            stack[len(stack)-2] =
+                math.Pow(stack[len(stack)-2], stack[len(stack)-1])
+            stack = stack[:len(stack)-1]
+        default:
+            action = "Push num onto top of stack"
+            f, _ := strconv.ParseFloat(tok, 64)
+            stack = append(stack, f)
+        }
+        fmt.Printf("%3s    %-26s  %v\n", tok, action, stack)
+    }
+    fmt.Println("\nThe final value is", stack[0])
+}