Main.java

import java.util.Scanner;
﻿
/**
 * Main.java
 * A simple game of guess the number.
 * @author Jose M Vidal <jmvidal@gmail.com>
 * Created on Jan 19, 2012
 * 
 */
public class Main {
﻿
	public static void main(String[] args) {
		final int secretLength = 4; //the number of digits in the secret. I can change this later if I want to make it harder
		Scanner keyboard = new Scanner(System.in);
		System.out.println("Guess the " + secretLength + "-digit number I am thinking of.");
		boolean done = false;
		int secretInteger = (int)(Math.random() * 10000);
		String secret = Integer.toString(secretInteger);
		while (secret.length() < secretLength) { //append 0's at the left of the number until it is of length 4
			secret = "0" + secret;
		}
		System.out.println("(the secret is " + secret + ")");
		while (! done){
			System.out.print("Your guess:");
			String guess = keyboard.next(); //Treating it like a string, not an int.
			if (guess.length() == secretLength) {
				int numCorrectDigits = 0; //the number of digits in correct position
				int numDigitsNotInSecret = 0; //the number of digits in guess that are nowhere in secret
				for (int index = 0; index < secretLength; index++){
					if (guess.charAt(index) == secret.charAt(index)) //at the correct position
						numCorrectDigits++;
					if (! secret.contains(guess.substring(index,index+1))){ //this digit is NOT in secret
						numDigitsNotInSecret++;
					}
				}
				System.out.println(guess + " has " + numCorrectDigits + " digits in the correct position.");
				System.out.println(guess + " has " + numDigitsNotInSecret + " digits that are not found anywhere in the secret number.");
				if (numCorrectDigits == secretLength)
					done = true;
			}
			else {
				System.out.println("Enter only a " + secretLength + "-digit number");
			}
		}
		System.out.println("Congratulations! You guessed correctly.");
	}
﻿
}