final read chapter 6

chapter6/average2/main.go

@@ -2,9 +2,28 @@ package main
 
 import (
 	"fmt"
+	"log"
 	"os"
+	"strconv"
 )
 
-func main() {
-	fmt.Println(os.Args)
+func average(numbers ...float64) float64 {
+	var sum float64 = 0
+	for _, number := range numbers {
+		sum += number
+	}
+	return sum / float64(len(numbers))
+}
+
+func main() {
+	arguments := os.Args[1:]
+	var numbers []float64
+	for _, argument := range arguments {
+		number, err := strconv.ParseFloat(argument, 64)
+		if err != nil {
+			log.Fatal(err)
+		}
+		numbers = append(numbers, number)
+	}
+	fmt.Printf("Average: %.2f\n", average(numbers...))
 }