Chapter 12

12.1.java

public class StringOps { 
   private String[] words; 

   public StringOps(String[] wordStrings){ 
      words = wordStrings; 
   } 

   public String stringHalf(boolean firstHalf) { 
      String finalString = "";
      for (String word : words) {
         if (firstHalf) {
            for (int i = 0; i < (word.length()/2); i++) {
               finalString = finalString + word.charAt(i);  
            }
         } else {
            for (int i = 0; i > (word.length()/2); i++) {
               finalString = finalString + word.charAt(i);  
            }
         }
      }
      return finalString;
   } 

   public String stringLetterSelect(int letterIndex) 
   { 
      String finalString = "";
      for (String word : words) {
         if (word.length() - 1 >= letterIndex) {
            finalString = finalString + word.charAt(letterIndex);
         }
      }
      return finalString;
   } 
}

12.2.java

public class BlackAndWhite {
   public String[][] blackOrWhite(String[][] colorArray) {
      for (int i = 0; i < colorArray.length; i++) {
         for (int j = 0; j < colorArray[i].length; j++) {
            if (colorArray[i][j].equals("0")) {
               colorArray[i][j] = "BLACK";
            } else if (colorArray[i][j].equals("255")) {
               colorArray[i][j] = "WHITE";  
            }
         }
      }
                
      return colorArray;
   }
}

12.3.java

import java.util.ArrayList;

public class StringSearch {
   public int findString(String inputStr, String searchStr) {
      return inputStr.indexOf(searchStr);

   }
    
   public void addString(String inputStr, int strIndex, ArrayList<String> wordsList) {
      wordsList.add(inputStr.substring(strIndex, strIndex+3));  
   }
}

12.4.java

public class ReversePalindrome {
   String reversedStr = "";
   public String wordReverse(String originalStr) {
      String reversed = "";
      char[] originalChars = originalStr.toCharArray();
      for (int i = originalChars.length - 1; i >= 0; i--) {
         reversed += originalChars[i];  
      }
      return reversed;
   }
    
   public boolean isPalindrome(String originalStr) {
      if (originalStr.equals(wordReverse(originalStr))) {
         return true;  
      } else return false;
   }
}

12.5.java

import java.util.ArrayList;

public class SentenceSplitter {
   public ArrayList<String> sentenceSplitter(String sentenceStr){
      ArrayList<String> words = new ArrayList<String>();
      for (String s : sentenceStr.split(" ")) {
         words.add(s);
      }
      return words;
   }
}

12.6.java

public class SentenceManager {       
    public double getVowels(String sentenceStr) {
       double total = 0.0;
       for (char c : sentenceStr.toCharArray()) {
         if ("aeiou".indexOf(c) > -1) {
            total += 1.0;  
         } else if (c == 'y') {
            total += 0.5;  
         }
       }
       return total;
    }
   
   public int getConsonants(String sentenceStr) {
      int total = 0;
      for (char c : sentenceStr.toCharArray()) {
         if ("aeiou ".indexOf(c) < 0) total += 1;
      }
      return total;
   }
}