// This program demonstrates some basic usage of booleans types
//   and values. Notice the use of good "Boolean zen" and the
//   "innocent until proven guilty" pattern in the gotHeads
//   method.
import java.util.*;

public class GamesOfChance {
   public static void main(String[] args) {
      Random rand = new Random();
      
      for (int i = 0; i < 5; i++) {
         System.out.println(countHeads(10, rand));
      }
      System.out.println();
      
      for (int i = 0; i < 5; i++) {
         // Bad Boolean zen - DON'T DO THIS!!
         // if (gotHeads(3, rand)) == true) {
         if (gotHeads(3, rand)) {
            System.out.println("Found a heads!");
         }
      }
      System.out.println();
   }
   
   // Write a method countHeads that takes an integer and a Random 
   // object as parameters and simulates flipping a coin the given 
   // number of times. The method hsould return the number of flips
   // that came up "heads." 
   //
   // int numFlips - the maximum number of times to flip   
   // Random rand - the Random object to use for randomization   
   public static int countHeads(int numFlips, Random rand) {
      int numHeads = 0;
      for (int i = 0; i < numFlips; i++) {
         int flip = rand.nextInt(2);
         if (flip == 0) {
            numHeads++;
         }
      }
      return numHeads;
   }
   
   // Write a method gotHeads that takes an integer and a Random 
   // object as parameters and simulates flipping a coin at most 
   // the given number of times. The method should return true 
   // if at least one flip comes up "heads" and false if all flips
   // come up "tails."
   //
   // int numFlips - the maximum number of times to flip   
   // Random rand - the Random object to use for randomization
   public static boolean gotHeads(int numFlips, Random rand) {
      for (int i = 0; i < numFlips; i++) {
         int flip = rand.nextInt(2);
         if (flip == 0) {     // 0 -> heads, 1 -> tails
            return true;
         }
      }
      return false;
   }
}