add chapter 6

chapter6/average/main.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+	"headfirstgo/headfirstgo/chapter6/datafile"
+	"log"
+)
+
+func main() {
+	numbers, err := datafile.GetFloats("data.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	var sum float64 = 0
+	for _, number := range numbers {
+		sum += number
+	}
+	sampleCount := float64(len(numbers))
+	fmt.Printf("Average: %.2f\n", sum/sampleCount)
+}