Java 227 - Exam 2 Review Guide Solutions

ExamReviewSolutions.java

package exam2review;

import java.util.ArrayList;
/*
 * <<<<NOTE>>>>>>>
 * Please work the review on your OWN first! It will help your understanding immensely.
 * only use this guide to check your own work.
 *
 * To Use:
 * 		-Make a package called "exam2review".
 * 		-Create a class called "ExamReviewSolutions".
 * 		-Paste this code into that class.
 */
public class ExamReviewSolutions {
		//Setup variables
		static double[] doublearray = {3.5,15.2,6.2};
		static String sentence = "The lazy brown fox jumped over the fence.";
		static String nonalpha = "Hello, world!";
		static ArrayList<Integer> intList = new ArrayList<Integer>();
		
		public static void main(String[] args)
		{
			//This Main tests all of the method solutions below.
			//Try playing around with some of the values!
			System.out.println("[Exam 2 Review Solutions]\n->Checkout the source!<-");
			System.out.println("Question 1a) 8.3 = "+q1a(doublearray));
			System.out.println("Question 1b) jumped = "+q1b(sentence));
			System.out.println("Question 1c) Hello##World# = "+q1c(nonalpha));
			System.out.println("Question 1d) 25 = "+q1d(.04,2000));
			
			intList.add(1);intList.add(2);intList.add(3);intList.add(4);
			System.out.println("Question 1e) Increasing? = "+q1e(intList));
			intList.add(2);intList.add(1);intList.add(10);intList.add(1);
			System.out.println("Question 1e) Increasing? = "+q1e(intList));
			
			System.out.println("Question 1f) 1 = "+q1f(nonalpha));
			
		}
	 
		public static double q1a(double[] array)
		{	
			//Initialize total variable.
			double total = 0;
			//Iterate over the array.						
			for(int i=0; i< array.length; i++)		
			{	
				//Add each new value to total.
				total+=array[i];					
			}
			//Divide by number of values and return.
			return total/array.length;				
		}
		
		public static String q1b(String sentence)
		{	
			//Split the sentence into an array of words.	
			String wordlist[] = sentence.split(" ");
			//Initialize the variable for the longest word.		
			String longest = "";							
			//Iterate over the words in the array.
			for(int i=0; i<wordlist.length; i++)			
			{
				//If the current word is bigger than the longest, replace longest with that word.
				if(wordlist[i].length() > longest.length())	
					longest = wordlist[i];	
			}
			return longest;
		}
		
		public static String q1c(String phrase)
		{	
			//Convert the string into an array (because Strings are immutable)
			char[] characters = phrase.toCharArray();
			//Iterate through the characters.
			for(int i=0; i<characters.length; i++)			
			{
				//If the Character is NOT a letter, swap it for a '#'.
				if(!Character.isLetter(characters[i]))
					characters[i] = '#';
			}
			//Change the array into a string again.
			phrase = String.valueOf(characters);
			return phrase;
		}
		
		public static int q1d(double givenRate, double givenBalance)
		{	
			/*Note: I know there's a mathematical way to do this.
			 * I'm using loops because the focus of this exam is 
			 * not on your math abilities. */
			
			//Months must be declared outside of the loop.
			int months = 0; double balance = givenBalance;
			//Loop until the balance is doubled. Note the exit condition!
			while(balance<givenBalance*2)
			{
				//Increase the balance and increment the month.
				balance+=givenBalance*givenRate;
				months++;
			}
			return months;

		}
		
		@SuppressWarnings("unused")
		public static boolean q1e(ArrayList<Integer> list)
		{	
			boolean flag = true;
			//Loop through ArrayList
			for(int i=1; i<list.size(); i++)
			{
				//If one element is not bigger than the next, return false
				if(!(list.get(i-1)<list.get(i)))
					flag = false;
			}
			return flag;
		}
		
		public static int q1f(String phrase)
		{	
			//Sanitize the string
			phrase=phrase.toUpperCase();
			//Initialize i outside of for loop (due to scope)
			int i;
			for(i=0; i<phrase.length(); i++)
			{	
				//If a character is in the list of vowels, break;
				if("AEIOU".contains(phrase.charAt(i)+""))
					break;
			}
			return i;
		}
}