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Java Java Objects Creating the MVP Conference Registration Assistant

KJ Han
KJ Han
987 Points

I do not know what step to take next!

Ok, so the mission is to sort given last names based on their first letter. For example, if the first letter of a last name is in between A to M, it should return 1. If it is between N to Z, it should return 2.

I currently do not have enough knowledge/experience in Java to tackle this problem... Any suggestions or help to get through this problem will be much appreciated!

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 firstLetter = lastName.charAt(0);
    if (firstLetter
    /*
      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

The Example.java class gives you a hint: you can compare characters to find out if they are before or after each other in the alphabet. So what you need to do is get the first character of the string. Then you can compare it with the 'N' character. If it's before 'N' (smaller than 'N') the result is line 1, otherwise the result is line 2.

Have a look at the java doc of String, got the "Methods" section, and look for a method that returns a char. You should be able to find one you can use to get the first character.

KJ Han
KJ Han
987 Points

Thanks for your advice, I found it very helpful! Have a nice day :)