average.go updated to process a file of numbers provide via commandline

average.go

@@ -1,13 +1,44 @@
 package main
 
-import "fmt"
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+
+	"git.linuxhg.com/john-okeefe/keyboard"
+)
+
+func Error(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
+	return
+}
 
 func average() {
-	numbers := [3]float64{71.8, 56.2, 89.5}
+	fmt.Printf("What is the name of the file: ")
+	fileString, err := keyboard.GetString()
+	Error(err)
+	fileString = strings.TrimSpace(fileString)
+	file, err := os.Open(fileString)
+	Error(err)
 	var sum float64 = 0
-	for _, number := range numbers {
+	scanner := bufio.NewScanner(file)
+	counter := 0
+	for scanner.Scan() {
+		number, err := strconv.ParseFloat(scanner.Text(), 64)
+		Error(err)
 		sum += number
+		counter++
 	}
-	sampleCount := float64(len(numbers))
+	err = file.Close()
+	Error(err)
+	if scanner.Err() != nil {
+		log.Fatal(scanner.Err())
+	}
+	sampleCount := float64(counter)
 	fmt.Printf("Average: %0.2f\n", sum/sampleCount)
 }