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Java Java Objects Creating the MVP Conference Registration Assistant

Damjan Vlaic
Damjan Vlaic
19,244 Points
Posted by Damjan Vlaic
Damjan Vlaic
19,244 Points

---JAVA---

can someone help with this, i've tried something in the method(it doesn't give me errors but doesn't do the right thing it should)

I've created a tool to help manage lines at tech conferences. The organizers would like to split the attendees into two lines during the registration process. I've added notes, examples and a new lesson in the Example.java tab.

Fix the getLineNumberFor method to return a 1 if the first character of lastName is between A and M or else return 2 if it is between N and Z.

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;
    for (char alphabet = 'a'; alphabet <= 'm'; alphabet++) {
      if (lastName.charAt(0) == alphabet) {
      lineNumber = 1;
      }
    }

    for (char alphabett = 'n'; alphabett <= 'z'; alphabett++) {
      if (lastName.charAt(0) == alphabett) {
      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

andren
andren
28,558 Points
andren
andren
28,558 Points

Remember that Java is case-sensitive. m and M are not considered the same character as far as it is concerned. In your code you are only going though lowercase letters, which does not work since the method is being called with a last name starting with a capital letter.

Changing all of the lowercase letters in your code into uppercase ones would work, but I would like to add that your code is actually quite complex and inefficient compared to what the challenge actually requires.

Instead of looping though all of the letters you can instead just directly check if lastName.charAt(0) is lesser or equal to M and then use an else statement for the other line.

Like this:

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;

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

}

Also one other somewhat unrelated note. I noticed that you seemed to go out of your way to use a different name for the alphabet variable in your second for loop.

The variables created by for loops are scoped to the loop, which means that they only exist within the loop. This means that you can safely reuse them outside the loop or within other loops. So you could have used alphabet as the name of the variable for both of the loops without causing any problems.

Edit: Fixed a logic issue with the initial code I had posted.