/*
Marty Stepp, CSE 142
Asks the user to do adding problems and scores them.
Example output:

4 + 10 + 3 + 10 = 27
9 + 2 = 11
8 + 6 + 7 + 9 = 25
Wrong! The answer was 30
5 + 9 = 13
Wrong! The answer was 14
4 + 9 + 9 = 22
3 + 1 + 7 + 2 = 13
4 + 2 + 10 + 9 + 7 = 42
Wrong! The answer was 32
You earned 4 total points.
*/

import java.util.*;

public class AddingGame {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        Random rand = new Random();
        
        // stop when they get 3 wrong
        int wrong = 0;
        int right = 0;
        while (wrong < 3) {
            int score = play(console, rand);
            if (score == 0) {
                // user got it wrong
                wrong++;
            } else {
                // user got it right (score == 1)
                right++;
            }
        }
        
        System.out.println("You earned " + right + " total points.");
    }
    
    // Plays one addition problem, picking 2-5 random numbers from 1-10.
    // Returns 1 if the user scored a point (got it right), and 0 if not.
    public static int play(Scanner console, Random rand) {
        // pick 2-5 randomly generated numbers
        int count = rand.nextInt(4) + 2;   // 2-5
        
        // handle fencepost problem by grabbing 1st number outside loop
        int answer = rand.nextInt(10) + 1;
        System.out.print(answer);
        
        // pick the remaining numbers (first one was picked before loop)
        for (int i = 2; i <= count; i++) {
            int num = rand.nextInt(10) + 1;
            answer += num;
            System.out.print(" + " + num);
        }
        System.out.print(" = ");
        
        // read user's guess and check whether it is correct
        int guess = console.nextInt();
        if (guess == answer) {
            return 1;
        } else {
            System.out.println("Wrong! The answer was " + answer);
            return 0;
        }
    }
}