Question

/**
   * Returns the string formed by alternating the case of the characters in
   * the specified string. The first character in the returned string is in
   * lowercase, the second character is in uppercase, the third character is
   * in lowercase, the fourth character is in uppercase, and so on.
   * Examples:
   *
   * <ul>
   * <li><code>alternatingCaps("a")</code> returns <code>"a"</code>
   * <li><code>alternatingCaps("ab")</code> returns <code>"aB"</code>
   * <li><code>alternatingCaps("abc")</code> returns <code>"aBc"</code>
   * <li><code>alternatingCaps("XYZ")</code> returns <code>"xYz"</code>
   * <li><code>alternatingCaps("Toronto")</code> returns <code>"tOrOnTo"</code>
   * <li><code>alternatingCaps("eecs2030")</code> returns <code>"eEcS2030"</code>
   * </ul>
   *
   * <p>
   * The conversion of characters to lower or uppercase is identical to
   * that performed by the methods <code>Character.toLowerCase(int)</code>
   * and <code>Character.toLowerCase(int)</code>
   *
   * @param s
   *            a string
   * @return the string formed by alternating the case of the characters in s
   */
   public static String alternatingCaps(String s) {
       return "";
   }

Answer 1

public class AlternatingCaps {

    /**
     * Returns the string formed by alternating the case of the characters in
     * the specified string. The first character in the returned string is in
     * lowercase, the second character is in uppercase, the third character is
     * in lowercase, the fourth character is in uppercase, and so on.
     * Examples:
     *
     * <ul>
     * <li><code>alternatingCaps("a")</code> returns <code>"a"</code>
     * <li><code>alternatingCaps("ab")</code> returns <code>"aB"</code>
     * <li><code>alternatingCaps("abc")</code> returns <code>"aBc"</code>
     * <li><code>alternatingCaps("XYZ")</code> returns <code>"xYz"</code>
     * <li><code>alternatingCaps("Toronto")</code> returns <code>"tOrOnTo"</code>
     * <li><code>alternatingCaps("eecs2030")</code> returns <code>"eEcS2030"</code>
     * </ul>
     *
     * <p>
     * The conversion of characters to lower or uppercase is identical to
     * that performed by the methods <code>Character.toLowerCase(int)</code>
     * and <code>Character.toLowerCase(int)</code>
     *
     * @param s a string
     * @return the string formed by alternating the case of the characters in s
     */
    public static String alternatingCaps(String s) {
        String result = "";
        for (int i = 0; i < s.length(); i++) {
            if (i % 2 == 0) {
                result += Character.toLowerCase(s.charAt(i));
            } else {
                result += Character.toUpperCase(s.charAt(i));
            }
        }
        return result;
    }

    public static void main(String[] args) {
        System.out.println(alternatingCaps("a"));
        System.out.println(alternatingCaps("ab"));
        System.out.println(alternatingCaps("abc"));
        System.out.println(alternatingCaps("XYZ"));
        System.out.println(alternatingCaps("Toronto"));
        System.out.println(alternatingCaps("eecs2030"));
    }
}