How to retrieve the first character in a string and compare it

Question

Hi there,

The solution to this problem suggests that we need to compare chars using the < and > operators however we only have a string as an argument to the method.

I've re-watched the previous lecture and can't see that it was explained how to get the first character from a string, store it in a char and compare it. The indexOf method returns a type of int, so we can't for example do char firstCharacter = lastName.indexOf(0); Also I can't see that a boolean check from the lecture is appropriate as that was a check for a character at any point in the string whereas we need to check the character at the first index.

Can anyone help with my thinking to solve this problem?

Many thanks,

Answer 1 · 2016-03-07T18:58:04Z

March 7, 2016 6:58pm

You need to set the value of the variable line to 1 if the last name starts with an M, otherwise to 2. The easiest way to see if a String starts with a particular letter is to use charAt(0), which returns the first letter (the first char) in the String. (Think of Strings as a collection of chars.) As the challenge says, you can use the comparative operators <, >, etc. to compare chars. This code compares the first letter (the first char) to M. If the char is less than M it assigns the person to the first line. Otherwise it assigns the person to the second line.

  public int getLineFor(String lastName) {
    /* If the last name is between A thru M send them to line 1
       Otherwise send them to line 2 */
    int line = 0;
    if (lastName.charAt(0) < 'M') {
      line = 1;
    } else {
      line = 2;
    }
    return line;
  }

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Matt O'Connor

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How to retrieve the first character in a string and compare it

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jcorum

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Matt O'Connor

Matt O'Connor