/*
Marty Stepp, CSE 142, Autumn 2008
Asks the user to do multiplication problems and score them.

Example output:
14 * 8 = 112
Correct!
5 * 12 = 60
Correct!
8 * 3 = 24
Correct!
5 * 5 = 25
Correct!
20 * 14 = 280
Correct!
19 * 14 = 256
Incorrect; the answer was 266

You solved 5 correctly
Last correct answer was 280
*/

import java.util.*;

public class MultiplicationTutor {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        Random rand = new Random();
        
        // fencepost solution - pull first question outside of loop
        int correct = 0;
        int last = ask(console, rand);
        int lastCorrect = 0;

        // loop until user gets one wrong
        while (last != 0) {
            lastCorrect = last;
            correct++;
            last = ask(console, rand);
        }
        
        System.out.println("You solved " + correct + " correctly");
        if (correct > 0) {
            System.out.println("Your last correct answer was " + lastCorrect);
        }
    }
    
    // Asks the user one multiplication problem,
    // returning true if they get it right and false if not.
    public static int ask(Scanner console, Random rand) {
        // pick two random numbers between 1 and 20 inclusive
        int num1 = rand.nextInt(20) + 1;
        int num2 = rand.nextInt(20) + 1;
        
        System.out.print(num1 + " * " + num2 + " = ");
        int answer = console.nextInt();
        if (answer == num1 * num2) {
            System.out.println("Correct!");
            return answer;
        } else {
            System.out.println("Incorrect; the correct answer was " + (num1 * num2));
            return 0;
        }
    }
}