Task: Bulls and cows



C#: using System;

namespace BullsnCows
{
    class Program
    {
        
        static void Main(string[] args)
        {
            int[] nums = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
            KnuthShuffle<int>(ref nums);
            int[] chosenNum = new int[4];
            Array.Copy(nums, chosenNum, 4);

            Console.WriteLine("Your Guess ?");
            while (!game(Console.ReadLine(), chosenNum))
            {
                Console.WriteLine("Your next Guess ?");
            }
            
            Console.ReadKey();
        }

        public static void KnuthShuffle<T>(ref T[] array)
        {
            System.Random random = new System.Random();
            for (int i = 0; i < array.Length; i++)
            {
                int j = random.Next(array.Length);
                T temp = array[i]; array[i] = array[j]; array[j] = temp;
            }
        }

        public static bool game(string guess, int[] num)
        {
            char[] guessed = guess.ToCharArray();
            int bullsCount = 0, cowsCount = 0;

            if (guessed.Length != 4)
            {
                Console.WriteLine("Not a valid guess.");
                return false;
            }

            for (int i = 0; i < 4; i++)
            {
                int curguess = (int) char.GetNumericValue(guessed[i]);
                if (curguess < 1 || curguess > 9)
                {
                    Console.WriteLine("Digit must be ge greater 0 and lower 10.");
                    return false;
                }
                if (curguess == num[i])
                {
                    bullsCount++;
                }
                else
                {
                    for (int j = 0; j < 4; j++)
                    {
                        if (curguess == num[j])
                            cowsCount++;
                    }
                }
            }

            if (bullsCount == 4)
            {
                Console.WriteLine("Congratulations! You have won!");
                return true;
            }
            else
            {
                Console.WriteLine("Your Score is {0} bulls and {1} cows", bullsCount, cowsCount);
                return false;
            }
        }
    }
}



Java: import java.util.InputMismatchException;
import java.util.Random;
import java.util.Scanner;

public class BullsAndCows{
	public static void main(String[] args){
		Random gen= new Random();
		int target;
		while(hasDupes(target= (gen.nextInt(9000) + 1000)));
		String targetStr = target +"";
		boolean guessed = false;
		Scanner input = new Scanner(System.in);
		int guesses = 0;
		do{
			int bulls = 0;
			int cows = 0;
			System.out.print("Guess a 4-digit number with no duplicate digits: ");
			int guess;
			try{
				guess = input.nextInt();
				if(hasDupes(guess) || guess < 1000) continue;
			}catch(InputMismatchException e){
				continue;
			}
			guesses++;
			String guessStr = guess + "";
			for(int i= 0;i < 4;i++){
				if(guessStr.charAt(i) == targetStr.charAt(i)){
					bulls++;
				}else if(targetStr.contains(guessStr.charAt(i)+"")){
					cows++;
				}
			}
			if(bulls == 4){
				guessed = true;
			}else{
				System.out.println(cows+" Cows and "+bulls+" Bulls.");
			}
		}while(!guessed);
		System.out.println("You won after "+guesses+" guesses!");
	}

	public static boolean hasDupes(int num){
		boolean[] digs = new boolean[10];
		while(num > 0){
			if(digs[num%10]) return true;
			digs[num%10] = true;
			num/= 10;
		}
		return false;
	}
}