Question

Need help coding this List. Lists are a lot like arrays, but you’ll be using get, set, add, size and the like instead of the array index operators [].​

package list.exercises;
import java.util.List;
public class ListExercises {

   /**

   * Counts the number of characters in total across all strings in the supplied list;

   * in other words, the sum of the lengths of the all the strings.

   * @param l a non-null list of strings

   * @return the number of characters

   */

   public static int countCharacters(List<String> l) {

       return 0;
}

   /**

   * Splits a string into words and returns a list of the words.

   * If the string is empty, split returns a list containing an empty string.

   *

   * @param s a non-null string of zero or more words

   * @return a list of words

   */

   public static List<String> split(String s) {
return null;
}

   /**

   * Returns a copy of the list of strings where each string has been

   * uppercased (as by String.toUpperCase).

   *

   * The original list is unchanged.

   *

   * @param l a non-null list of strings

   * @return a list of uppercased strings

   */

   public static List<String> uppercased(List<String> l) {

       return null;

   }

   /**

   * Returns true if and only if each string in the supplied list of strings

   * starts with an uppercase letter. If the list is empty, returns false.

   *

   * @param l a non-null list of strings

   * @return true iff each string starts with an uppercase letter

   */

   public static boolean allCapitalizedWords(List<String> l) {

       return false;

   }

   /**

   * Returns a list of strings selected from a supplied list, which contain the character c.

   *

   * The returned list is in the same order as the original list, but it omits all strings

   * that do not contain c.

   *

   * The original list is unmodified.

   *

   * @param l a non-null list of strings

   * @param c the character to filter on

   * @return a list of strings containing the character c, selected from l

   */

   public static List<String> filterContaining(List<String> l, char c) {

       return null;

   }

  

   /**

   * Inserts a string into a sorted list of strings, maintaining the sorted property of the list.

   *

   * @param s the string to insert

   * @param l a non-null, sorted list of strings

   */

   public static void insertInOrder(String s, List<String> l) {

   }

}

Answer 1

import java.util.ArrayList;
import java.util.List;


public class ListExercises {

    /**

     * Counts the number of characters in total across all strings in the supplied list;

     * in other words, the sum of the lengths of the all the strings.

     * @param l a non-null list of strings

     * @return the number of characters

     */

    public static int countCharacters(List<String> l) {
        return l.size();
    }

    /**

     * Splits a string into words and returns a list of the words.

     * If the string is empty, split returns a list containing an empty string.

     *

     * @param s a non-null string of zero or more words

     * @return a list of words

     */

    public static List<String> split(String s) {
        List<String> list = new ArrayList<>();
        String[] arr = s.split(" ");

        for ( String ss : arr) {
            list.add(ss);
        }
        return list;
    }

    /**

     * Returns a copy of the list of strings where each string has been

     * uppercased (as by String.toUpperCase).

     *

     * The original list is unchanged.

     *

     * @param l a non-null list of strings

     * @return a list of uppercased strings

     */

    public static List<String> uppercased(List<String> l) {

        List<String> list = new ArrayList<>();
        for (String str : l) {
            list.add(str.toUpperCase());
        }

        return list;

    }

    /**

     * Returns true if and only if each string in the supplied list of strings

     * starts with an uppercase letter. If the list is empty, returns false.

     *

     * @param l a non-null list of strings

     * @return true iff each string starts with an uppercase letter

     */

    public static boolean allCapitalizedWords(List<String> l) {
        boolean isAllCaps = true;
        for (String str : l) {
            for (int i=0; i<str.length(); i++)
            {
                if (Character.isLowerCase(str.charAt(i)))
                {
                    isAllCaps = false;
                    break;
                }
            }
        }

        return isAllCaps;

    }

    /**

     * Returns a list of strings selected from a supplied list, which contain the character c.

     *

     * The returned list is in the same order as the original list, but it omits all strings

     * that do not contain c.

     *

     * The original list is unmodified.

     *

     * @param l a non-null list of strings

     * @param c the character to filter on

     * @return a list of strings containing the character c, selected from l

     */

    public static List<String> filterContaining(List<String> l, char c) {
        List<String> list = new ArrayList<>();
        for (String str : l) {
            if (str.indexOf(c) != -1) {
                list.add(str);
            }
        }
        return list;

    }



    /**

     * Inserts a string into a sorted list of strings, maintaining the sorted property of the list.

     *

     * @param s the string to insert

     * @param l a non-null, sorted list of strings

     */

    public static void insertInOrder(String s, List<String> l) {
        l.add(s);
        java.util.Collections.sort(l);
    }

}