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Java Java Objects Creating the MVP Conference Registration Assistant

Gabriel Favela
Gabriel Favela
1,565 Points

Need some help with charAt...

What the challenge is asking me to do is to return a 1 if the last name is between 'A' thru 'M', and return a 2 if it is between 'N' thru 'Z'. My code isn't compiling, I tried other ways of doing this but it keeps giving me syntax errors. I am a little stuck with this and don't want to waste more time then I already have. "you learn by asking"...

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;
    /*
      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.charAt('a' <= 'm')) {
      lineNumber = 1;
    }

    if (lastName.charAt('n' <= 'z')) {
      lineNumber = 2;
    }

    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

Felix Sonnenholzer
Felix Sonnenholzer
14,654 Points

Hi Gabriel,

you need to compare only the first letter in the String. charAt is expecting an index, but you are giving it a comparison. You need the comparison between the first char AND 'M' Try it that way.

// first letter in a String is Index 0
if (lastName.charAt(0) <= 'M') {
    lineNumber = 1;
} else {
// a simple if else statement should work in this case
   lineNumber = 2;
}

I hope that helped.