Error

Question

i dont know exactly what i do and so confused the error say: ./ConferenceRegistrationAssistant.java:26: error: missing return statement } ^ Note: JavaTester.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details.

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 ('A' < 'M') {
      return  lastName.charAt(0);
    }

    if ('N' > 'Z') {
      return lastName.charAt(1);
    }


  }

}

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");
  }

}

Answer 1 · 2017-03-28T19:21:39Z

March 28, 2017 7:21pm

Your return statements are essentially returning the first letter and second letter of the last name if A comes before M (first letter) and if N comes before Z (second letter). The first issue with this is that you are not returning an int like the function expects, which makes your returns sort of go out the window. The second issue is that you're not actually comparing the character you retrieve to the parameters (and, of course, you're retrieving the wrong letter in the second if statement). What should be happening is you need to get the .charAt(0) and probably store it as a Character variable which you can then pass into your conditionals as something like

if ('A' <= returnedChar && returnedChar <= 'M') {
    lineNumber = 1;  // Since the variable is already created, we could use 
                     // it and leave the return lineNumber at the end of the function, 
                     // or we can simply "return 1;" here and "return 2;" in the other conditional.
}

and we should be good.

If you decide to ditch the lineNumber variable in your ifs, you'll probably need to have a return statement outside of your conditionals, probably something like return 0; since it wants an int but you don't want to return a 1 or 2 since those are valid data if we meet our conditions in the above checks. Personally, I would just leave the lineNumber variable in place and have a single return statement at the end of the function, like the Challenge had set up from the start.

If you need more help, or didn't understand something I said, I'll try to clarify. Good luck! :)

Answer 2 · 2017-03-28T18:41:31Z

March 28, 2017 6:41pm

Looks like you're missing a return statement in the getLineNumberFor() method. You have return statements inside the scope of two IF statements, but Java will complain because not all logic branches have a return statement. In our mind, a letter should fall between A-M or N-Z, so it seems like all logic branches are returning a value, but Java just sees that two IF statements with nested return statements - it doesn't know that at least one of those IF statements will always apply to the parameter.

If you turn the second IF statement into an ELSE statement, then that should fix the error.

Let me know if you have any more questions.

Welcome to the Treehouse Community

Looking to learn something new?

mohamadreza azadi

mohamadreza azadi

Error

2 Answers

Mike Wagner

Mike Wagner

mohamadreza azadi

mohamadreza azadi

Mike Wagner

Mike Wagner

mohamadreza azadi

mohamadreza azadi

Mike Wagner

Mike Wagner

Chris Jones

Chris Jones

mohamadreza azadi

mohamadreza azadi

Chris Jones

Chris Jones