(Java) Not sure what the syntax error is?

Question

Not sure what the syntax error is in this part of the code based on the question below

if (lastName.charAt(0) == 'a','b','c','d','e','f','g','h','i','j','k','l','m')
{
lineNumber +=1;
} 
else{
 lineNumber +=2;
}    
return lineNumber;

}

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;
    /*
      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(0) == 'a','b','c','d','e','f','g','h','i','j','k','l','m')
    {
    lineNumber +=1;
    } 
    else{
     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");
  }

}

Answer 1 · 2018-11-28T19:09:35Z

November 28, 2018 7:09pm

You can only assign a single value to a char. Here, you're checking it against a list of different values, as if writing:

if (x == 10, 5, 3, 6, 15)      // which is not correct

One way would be to check the char against each value:

if (lastName.charAt(0) == 'A' || lastName.charAt(0) == 'B' || lastName.charAt(0) == 'C' ... )

but there is an easier way since we can compare chars, as we do numbers. So just like if you wanted to check if a number x was between 10 and 150 (incl) you would write: if (x >= 10 && x <=150), you can do the same with letters, checking if a char c is between A and M:

if (c >= 'A' && c <= 'M') 
// Use capital letters here as the comparison is case sensitive and last names start with a capital letter

The second point to be careful about is that you should not increment the value of the variable lineNumber, but rather set its value to either 1 or 2, accordingly. So, wrapping it all up, you get:

if (lastName.charAt(0) >= 'A' && lastName.charAt(0) <='M') {
     lineNumber = 1;
} else {
     lineNumber = 2;
}    
return lineNumber;
}

Hope this helps

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Tashfin Shahid

Tashfin Shahid

(Java) Not sure what the syntax error is?

1 Answer

Lauren Moineau

Lauren Moineau

Tashfin Shahid

Tashfin Shahid

Lauren Moineau

Lauren Moineau