add vance's solution (#43)

Author: VanceLongwill

students/vancelongwill/main.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"bufio"
+	"encoding/csv"
+	"flag"
+	"fmt"
+	"math/rand"
+	"os"
+	"strings"
+	"time"
+)
+
+func main() {
+	csvFilename := flag.String("f", "problems.csv", "csv file with 2 columns, question & answer")
+	timeLimit := flag.Int("t", 30, "the time limit for the quiz in seconds")
+	hasShuffle := flag.Bool("s", false, "randomize question order")
+	flag.Parse()
+
+	correctCount := 0
+	reader := bufio.NewReader(os.Stdin)
+
+	fmt.Println("Press enter to start the quiz")
+	reader.ReadBytes('\n')
+
+	b, fileErr := os.Open(*csvFilename)
+	if fileErr != nil {
+		fmt.Print(fileErr, "\nFailed to read the CSV file provided")
+		os.Exit(1)
+	}
+
+	r := csv.NewReader(b)
+	records, csvErr := r.ReadAll()
+
+	if csvErr != nil {
+		fmt.Print(csvErr, "\nFailed to parse the CSV file provided")
+		os.Exit(1)
+	}
+
+	timeout := time.NewTimer(time.Duration(*timeLimit) * time.Second)
+
+	ansCh := make(chan string)
+	getUserInput := func() {
+		userAns, _ := reader.ReadString('\n')
+		ansCh <- strings.TrimSpace(strings.ToLower(userAns))
+	}
+
+	if *hasShuffle {
+		rand.Shuffle(len(records), func(i, j int) {
+			records[i], records[j] = records[j], records[i]
+		})
+	}
+
+qLoop:
+	for i, record := range records {
+		fmt.Printf("Question %d:\t%s\t", i+1, record[0])
+		go getUserInput()
+
+		select {
+		case <-timeout.C:
+			fmt.Println("\nToo slow!")
+			break qLoop
+		case ans := <-ansCh:
+			if ans == record[1] {
+				correctCount++
+			}
+		}
+	}
+
+	fmt.Printf("You scored %d out of %d!\n", correctCount, len(records))
+}