Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Java Java Objects Creating the MVP Conference Registration Assistant

Samuel Lindkvist
Samuel Lindkvist
550 Points

What is wrong?

What is wrong?

ConferenceRegistrationAssistant.java
public class ConferenceRegistrationAssistant {

  /**
   * Assists in guiding people to the proper line based on their last name.
   *
   * @param lastName The person's last name
   * @return The line number based on the first letter of lastName
   */
  public int getLineNumberFor(String lastName) {
    int lineNumber = 0;
    char oneLetter = lastName.charAt(0);
    if(oneLetter >= 'a' && oneLetter <= 'm'){
      lineNumber = 1;
    } 
     else if(oneLetter >= 'n' && oneLetter <= 'z'){
      lineNumber = 2;
    } 
    /*
      lineNumber should be set based on the first character of the person's last name
      Line 1 - A thru M
      Line 2 - N thru Z

     */
    return lineNumber;
  }

}
Example.java
public class Example {

  public static void main(String[] args) {
    /*
      IMPORTANT:  You can compare characters using <, >. <=, >= and == just like numbers
     */
    if ('C' < 'D') {
      System.out.println("C comes before D");
    }

    if ('B' > 'A') {
      System.out.println("B comes after A");
    }

    if ('E' >= 'E') {
      System.out.println("E is equal to or comes after E");
    }

    // This code is here for demonstration purposes only...
    ConferenceRegistrationAssistant assistant = new ConferenceRegistrationAssistant();
    /*
      Remember that there are 2 lines.
      Line #1 is for A-M
      Line #2 is for N-Z
     */
    int lineNumber = 0;
    /*
      This should set lineNumber to 2 because
      The last name is Zimmerman which starts with a Z.
      Therefore it is between N-Z
     */
    lineNumber = assistant.getLineNumberFor("Zimmerman");

    /*
      This method call should set lineNumber to 1, because 'A' from "Anderson" is between A-M.
     */
    lineNumber = assistant.getLineNumberFor("Anderson");

    /*
      Likewise Charlie Brown's 'B' is between 'A' and 'M', so lineNumber should be set to 1
     */
    lineNumber = assistant.getLineNumberFor("Brown");
  }

}

1 Answer

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there! You're doing terrific! Your syntax is spot on, your code is easy to read and clean, and your comparisons are doing almost what they're supposed to be doing. You're just missing one tiny thing.

Remember, computers don't really know what a letter is. When you hit a key on your keyboard, the computer doesn't see a letter... it sees a number. These numbers are defined by different encoding systems etc. This is why we can compare letters in the manner we're doing here. But this also means that a lower case "a" has a different value than an upper case "A". The first letter of the last name will be a capital letter.

You can fix this in one of two ways:

  • Change the comparisons to check against "A" and "M", and "N" and "Z" instead of their lower case versions
  • Turn the last name to all lower case with the toLowerCase() function and assign it back into lastName

Hope this helps! :sparkles: