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Java Java Objects Creating the MVP Conference Registration Assistant

Angelos Kalandranis
Angelos Kalandranis
661 Points

I keep getting a message that an M name is added to the second line. Is there some mistake in my code or my approach?

Should I have imported Scanner?

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 String lastName;
  public int getLineNumberFor(String lastName) {
    int lineNumber = 0;
    if(lastName.charAt(0)<= 13){
      lineNumber= lineNumber + 1;
    }else{
      lineNumber= 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");
  }

}

2 Answers

Ronald Williams
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Ronald Williams
Java Web Development Techdegree Graduate 25,021 Points

charAt returns a char not a number. So if the name is Nelson your statement would be: 'N' <= 13. You are comparing a letter to a number. Here is what you can do instead: (I added the method toLowerCase() incase someone forgets to capitalize their last name)

  public int getLineNumberFor(String lastName) {
    int lineNumber = 0;
    /*
      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

     */
    if (lastName.toLowerCase().charAt(0) < 'n') {
      lineNumber = 1;
    }
    if (lastName.toLowerCase().charAt(0) > 'm') {
      lineNumber = 2;
    }
    return lineNumber;
  }
Seth Kroger
Seth Kroger
56,413 Points

Although char is essentially a number and can be treated as such, that does not mean the alphabet starts at 1. chars have to represent all sorts of characters like space, '3', '^', etc., and their value depends on their character encoding, the mapping from number to character (Unicode UTF-16 for Java chars and Strings.). It is better to use character literals here instead of numbers, which you'll find to be less error prone and easier to understand then using "magic numbers" in your code.