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Java Java Objects Creating the MVP Conference Registration Assistant

Sorting into two lines

I don't understand how this problem works or what it's supposed to be.

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 lastName = lastNameInput.charAt(0);
    if (lastName >= A || <= M){
    return lineNumber = 1;
    } else {
      return lineNumver = 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

Johan Cederschiöld
Johan Cederschiöld
5,708 Points

The "mission" is to fix the getLineNumberFor method so that it returns the correct line number based on the lastname.

The method takes a String (the lastName) as the parameter and should return an int, the lineNumber.

Ok, so how do we do this.

Firstly we'll need the first letter of the lastName. We can get this with the charAt(n) method which you can apply to a String.

lastName.charAt(0) will return the first letter of the String, since the index goes from 0 (as in arrays for example). This allows you to compare the first letter and sort it.

Example:

if (lastName.charAt(0) < 'N' ) { lineNumber = 1; } else { lineNumber = 2; }

return lineNumber;

Why 'N' and not 'M'? Well, I used the "less than" operator and people with a name starting with an M should be sorted in the first line.

Please come back if there's anything you feel needs more explaining.