add csos95 quiz implementation (gophercises#4)

students/csos95/main.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+	"bufio"
+	"encoding/csv"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+	"time"
+)
+
+var (
+	// set flags
+	csvPath = flag.String("csv", "problems.csv", "a csv file in the format of 'question,answer'")
+	limit   = flag.Int("limit", 30, "the time limit for the quiz in seconds'")
+)
+
+func main() {
+	// parse the flags
+	flag.Parse()
+
+	// open the csv file
+	file, err := os.Open(*csvPath)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	defer file.Close()
+
+	// open the csv file
+	csvReader := csv.NewReader(file)
+	// parse the csv file
+	csvData, err := csvReader.ReadAll()
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	// put question/answer pairs into a map where questions are keys and answers are values
+	qaPair := make(map[string]string, len(csvData))
+	for _, data := range csvData {
+		qaPair[data[0]] = data[1]
+	}
+
+	// create a ticker for the time limit and a channel to signal the user finished the quiz
+	ticker := time.NewTicker(time.Second * time.Duration(*limit))
+	done := make(chan bool)
+
+	// create a scanner for user input
+	scanner := bufio.NewScanner(os.Stdin)
+
+	var userAnswer string
+	qNum, numCorrect := 0, 0
+	go func() {
+		// iteration order for maps in go is randomized so the questions won't be in the same order every time
+		for question, answer := range qaPair {
+			qNum++
+			// ask a question
+			fmt.Printf("Problem #%d: %s = ", qNum, question)
+			// get an answer
+			scanner.Scan()
+			userAnswer = scanner.Text()
+			// trim leading and trailing whitespace
+			userAnswer = strings.TrimSpace(userAnswer)
+			userAnswer = strings.ToLower(userAnswer)
+			answer = strings.ToLower(answer)
+			// check the answer
+			if answer == userAnswer {
+				numCorrect++
+			}
+		}
+		done <- true
+	}()
+
+	// select chooses the first channel with an available value
+	// if done is available first, the user finished
+	// if ticker is available first, the time limit has been reached
+	select {
+	case <-done:
+	case <-ticker.C:
+		fmt.Println("time's up!")
+	}
+
+	// print the results
+	fmt.Printf("You scored %d out of %d.\n", numCorrect, len(qaPair))
+}

students/csos95/problems.csv

@@ -0,0 +1,12 @@
+5+5,10
+1+1,2
+8+3,11
+1+2,3
+8+6,14
+3+1,4
+1+4,5
+5+1,6
+2+3,5
+3+3,6
+2+4,6
+5+2,7