CSE 142: Computer Programming I, Summer 2012

Homework 6 (Baby Names) FAQ

Q: How do I get started?

A: Read Ch. 6 in the textbook. Look over the and Temperatures and Cities example from lecture.

Q: Why does my prompt get all messed up when the user types more than one word on the console?

A: Make sure to choose the right method(s) for reading user input. If you want a one-word answer, use the Scanner object's next method. If you want to allow a multi-word answer, use nextLine instead.

Q: Why do I get a NoSuchElementException?

A: You tried to read past the end of a Scanner. Read the exception output text carefully and look for the first line that mentions your program. That's the line that is the culprit. For example, the output:

Exception in thread "main" java.util.NoSuchElementException
          at java.util.Scanner.throwFor(Scanner.java:838)
          at java.util.Scanner.next(Scanner.java:1347)
          at MyProgram.sillyMethod(MyProgram.java:39)
          at MyProgram.main(MyProgram.java:15)
    

means that there's an error in sillyMethod at line 39 of MyProgram.java.

Q: Why do I get an InputMismatchException?

A: You tried to read the wrong type of token from a Scanner. For example, you tried to read the word "Lisa" as an int.

Q: How do I make a Scanner start over or go back?

A: You can't! But if it is a String Scanner, you can make a new Scanner over the same String to start reading over again.