University of Washington, CSE 142
Lab 6: File Processing
Except where otherwise noted, the contents of this document are
Copyright 2013 Stuart Reges and Marty Stepp.
lab document created by Marty Stepp, Stuart Reges and Whitaker Brand
Basic lab instructions
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Mouse over highlighted words if you're not sure what they mean!
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Talk to your classmates for
help.
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You may want to bring your textbook to future labs
to look up syntax and examples.
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Stuck? Confused? Have a question? Ask a TA for
help, or look at the book or past .
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Complete as much of the lab as you can within the allotted time. You don't need to keep working on these exercises after you leave.
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Feel free to complete problems in any order.
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Make sure you've signed in on the sign-in sheet before you leave!
Today's lab
Goals for today:
- use
Scanner and File objects to read input data from files
- understand the way a
Scanner breaks input into tokens
- get more practice using
Strings
- explore token-based and line-based input
- Where you see this icon, you can click it to check the problem in Practice-It!
Scanner methods
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Method name
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Description
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next()
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reads and returns the next token as a String
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nextLine()
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reads and returns as a String all the characters up to
the next new line (\n)
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nextInt()
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reads and returns the next token as an int, if
possible
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nextDouble()
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reads and returns the next token as double, if
possible
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hasNext()
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returns true if there is still a token in
the Scanner
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hasNextLine()
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returns true if there is still at least one line left
to be read in the Scanner
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hasNextInt()
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returns true if the next token can be read as
an int
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hasNextDouble()
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returns true if the next token can be read as
an double
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[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]
If you finish them all...
If you finish all the exercises, try out
our Practice-It
web tool. It lets you solve Java problems from our Building Java
Programs textbook.
You can view an exercise, type a solution, and submit it to see if you
have solved it correctly.
Choose some problems from the book and try to solve them!