Solutions for part 1 and 2 (gophercises#47)

* Solutions for part 1 and 2

* Time limit to end quiz without waiting for next input

students/bart/main.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bufio"
+	"encoding/csv"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"time"
+)
+
+func fatalError(message string, err error) {
+	if err != nil {
+		log.Fatalln(message, ":", err)
+	}
+}
+
+type question struct {
+	question string
+	answer   string
+}
+
+type quiz struct {
+	answered          int
+	answeredCorrectly int
+	questions         []question
+}
+
+// loadQuiz loads all questions into memory, assumed to be safe as
+// the instructions state that the quiz will be < 100 questions
+func loadQuiz(filePath string) *quiz {
+	csvFile, err := os.Open(filePath)
+	fatalError("Error opening quiz CSV file", err)
+	defer csvFile.Close()
+	reader := csv.NewReader(bufio.NewReader(csvFile))
+	var quiz quiz
+	for {
+		line, err := reader.Read()
+		if err == io.EOF {
+			break
+		}
+		fatalError("Error parsing CSV", err)
+		question := question{line[0], line[1]}
+		quiz.questions = append(quiz.questions, question)
+	}
+	return &quiz
+}
+
+// run prints questions, check answers, and records total
+// answered and total correct
+func (quiz *quiz) run() {
+	timer := time.NewTimer(time.Duration(*timeLimit) * time.Second)
+quizLoop:
+	for _, question := range quiz.questions {
+		fmt.Println(question.question)
+		answerCh := make(chan string)
+		go func() {
+			scanner.Scan()
+			answer := scanner.Text()
+			answerCh <- answer
+		}()
+		select {
+		case <-timer.C:
+			break quizLoop
+		case answer := <-answerCh:
+			if answer == question.answer {
+				quiz.answeredCorrectly++
+			}
+			quiz.answered++
+		}
+	}
+	return
+}
+
+// report prints summary of quiz performance
+func (quiz *quiz) report() {
+	fmt.Printf(
+		"You answered %v questions out of a total of %v and got %v correct",
+		quiz.answered,
+		len(quiz.questions),
+		quiz.answeredCorrectly,
+	)
+}
+
+var (
+	scanner     = bufio.NewScanner(os.Stdin)
+	filePathPtr = flag.String("file", "./problems.csv", "Path to csv file containing quiz.")
+	timeLimit   = flag.Int64("time-limit", 30, "Set the total time in seconds allowed for the quiz.")
+)
+
+func main() {
+	quiz := loadQuiz(*filePathPtr)
+	quiz.run()
+	quiz.report()
+}