/* have the user input 6 lotto numbers from 1..50 and then auto-generate a 1 million lotto 
 * drawings and see how many numbers the user matched.  Output the average number of matched
 * numbers (this should be a value much less than 1, so output this with some precision) 
 * Use methods as much as possible.  */
 
 import java.util.*;				// need Random and Scanner
 
 public class Lotto
 {
 	public static void main(String[] args)
 	{
 		Scanner in = new Scanner(System.in);
 		Random g = new Random();
 		int[] user;
 		int[] lotto;
 		int numMatched = 0;
 		user = getPicks(in);					// get the user's 6 numbers, data verify that they are between 1..50 and no duplicates
 		for(int i=0;i<1000000;i++)
 		{
 			lotto = generateLotto(g);			// get 6 random numbers, data verify that there are no duplicates
 			numMatched += compare(user, lotto);	// returns the number that matched, add this to numMatched
 		}
 		double avgMatched = numMatched / 1000000.0;
 		System.out.printf("Out of 1 million attempts, the user's numbers matched %d times for an average of %5.3f per drawing\n", 
 			numMatched, avgMatched);
 	}
 	
 	// method to input the user picks (6 int values between 1 and 50 with no duplicates), uses data verification to ensure the
 	// 6 numbers are in the proper range and unique
 	public static int[] getPicks(Scanner in)
 	{
 		int[] temp = new int[6];				// array to store the 6 user numbers
 		int i, userPick;
 		boolean[] picked = new boolean[50];		// used to represent whether a given pick as been selected yet or not
 		for(i=0;i<50;i++) picked[i] = false;	// initialized to false to say that no number has yet been picked
 		for(i=0;i<6;i++)						// iterate 6 times to fill in the user array (temp)
 		{
 			do{
 				System.out.print("Enter your next lotto pick between 1 and 50  ");	// get the next user pick
 				userPick = in.nextInt();
 				userPick--;						// convert from 1..50 to 0..49 to fit with the picked array
 			}while(userPick<0||userPick>49||picked[userPick]);	// data verify legal number
 			temp[i] = userPick;					// add new pick to temp array
 			picked[userPick] = true;			// set userPick to true to indicate that number has been selected
 		}
 		return temp;							// return the user selected numbers
 	}
 	
 	// method to generate 6 random numbers from 0 to 49 (in this range because of the picked array), data verifying that each
 	// number is unique
 	public static int[] generateLotto(Random g)
 	{
 		int[] temp = new int[6];				// the array to store the random numbers
 		int i, randomPick;
 		boolean[] picked = new boolean[50];		// array to store whether a given number has been generated yet or not
 		for(i=0;i<50;i++) picked[i] = false;	// initialized to false because no numbers have been generated yet
 		for(i=0;i<6;i++)						// generate 6 random numbers
 		{
 			do{									// data verification loop to make sure the new number is unique
 				randomPick = g.nextInt(50);		// generate a number from 0 to 49 (instead of 1 to 50)
 			}while(picked[randomPick]);			// data verify
 			temp[i] = randomPick;				// place new number in temp array
 			picked[randomPick] = true;			// set userPick to true to indicate that the given number has been generated
 		}
 		return temp; 							// return the randomly generated 6 numbers
 	}
 	
 	// method to compare the two arrays of 6 numbers, u is the user's picks and l is the auto-generated lotto numbers
 	public static int compare(int[] u, int[] l)
 	{
 		int count = 0;							// count the number of matches
 		for(int i=0;i<6;i++)					// use two nested for loops so that we look at each u[i] and compare it to all 6 numbers in l
 			for(int j=0;j<6;j++)				// note that we are assured there are no duplicate numbers otherwise the logic becomes more complex
 				if(u[i]==l[j]) count++;			// on a match between the two arrays, count it
 		return count;							// return the total number of matches
 	}
 	
 }