// This file contains some sample methods that are similar to questions that might be
// asked on the midterm exam.
import java.util.*;

public class MidtermPractice {
   public static void main(String[] args) {
      System.out.println(doubleLetters("abcde"));
      System.out.println(doubleLetters("Mississippi"));
      System.out.println(doubleLetters("abracadabra"));
      System.out.println();  
      
      System.out.println(containsE("abcdefg"));
      System.out.println(containsE("cheese"));
      System.out.println(containsE("banana"));
      System.out.println(containsE("CSE"));
      System.out.println(containsE(""));
      System.out.println();

      Random rand = new Random();
      rollSeven(rand);
      System.out.println();
      rollSeven(rand);
      System.out.println();
      rollSeven(rand);
      System.out.println();
      System.out.println();    
   }
   
   // Write a static method called doubleLetters that takes a String as a parameter and 
   // returns a new String where each letter of the original string has been replaced with
   // two of that letter.  For example, doubleLetters("hello") should return "hheelllloo".   
   public static String doubleLetters(String str) {
      String result = "";
      for (int i = 0; i < str.length(); i++) {
         // result = result + str.substring(i, i + 1) + str.substring(i, i + 1);
         result = result + str.charAt(i) + str.charAt(i);
      }
      return result;
   }   
   
   // Write a static method called containsE that takes a single string parameter
   // and returns a true if the value passed contains an 'e' as one of its characters, 
   // and false otherwise. Your method should return true if an 'e' appears in either
   // lowercase or uppercase.
   public static boolean containsE(String str) {
      for (int i = 0; i < str.length(); i++) {
         char ch = str.toLowerCase().charAt(i);
         if (ch == 'e') {
            return true;
         }
      }
      return false;
   }

   // Write a static method called rollSeven that takes a Random object as a parameter
   // and simulates the rolling of two dice until their sum is equal to 7.  The method 
   // should print each roll and its sum and print the number of rolls it took to get 
   // to 7. Consider this sample execution:
   //     Roll #1: 3 + 5 = 8
   //     Roll #2: 2 + 1 = 3
   //     Roll #3: 1 + 4 = 5
   //     Roll #4: 3 + 4 = 7
   //     Found 7 in 4 rolls.
   // You must exactly reproduce the format of this sample execution.   
   public static void rollSeven(Random rand) {
      int total = 0;
      int count = 0;
      while (total != 7) {
         int roll1 = rand.nextInt(6) + 1;
         int roll2 = rand.nextInt(6) + 1;
         total = roll1 + roll2;
         count++;
         
         System.out.println("Roll #" + count + ": " + roll1 + " + " + roll2 + " = " + total);
      }
      System.out.println("Found 7 in " + count + " rolls.");
   }
}