package main

import (
	"bufio"
	"fmt"
	"math"
	"math/rand"
	"os"
	"strconv"
	"time"
)

func main() {
	for {
		rand.Seed(time.Now().UnixNano())
		fmt.Println("Train")
		fmt.Println("Creative Computing Morristown, New Jersey")
		fmt.Printf("Time - Speed Distance Exercise:")
		var car int = rand.Intn(65-40) + 40
		var distance int = rand.Intn(20-5) + 5
		var train int = rand.Intn(39-20) + 20
		fmt.Printf(" A Car traveling %d MPH can make a certain trip in %d hours less than a Train traveling at %d MPH.\n", car, distance, train)
		for {
			scanner := bufio.NewScanner(os.Stdin)
			fmt.Printf("\nHow long does the trip take by car ")
			scanner.Scan()
			answer, err := strconv.ParseFloat(scanner.Text(), 64)
			if err != nil {
				fmt.Println("Please enter a number")
				continue
			}
			var car_time int = distance * train / (car - train)
			var percent int = int(math.Abs((float64(car_time)-answer)*100/answer) + .5)
			if percent > 5 {
				fmt.Printf("Sorry, you were off by %d percent\n", percent)
				fmt.Printf("Correct answer is %d hours\n", car_time)
			} else {
				fmt.Printf("Good! Answer within %d percent\n", percent)
				fmt.Printf("Another Problem? (yes or no) ")
				scanner.Scan()
				if scanner.Text() == "yes" {
					break
				}
				return
			}
			continue
		}
	}
}