Programming

12 posts

Solve Perl “Wide Character in Print”

Here is a simple Perl program that outputs a capital gamma character (Ɣ): print "\x{194}\n". When you run it, you will probably get a warning from Perl about a "Wide character in print at line 1".

$ perl -e 'print "\x{194}\n"'
Wide character in print at -e line 1.
Ɣ

You can solve this using several different methods.

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TripAdvisor’s Hotel Availability Comparison

Since I spent about six months of my professional life working on TripAdvisor's hotel availability comparison feature, I thought a little writeup about it here would be appropriate. If you fill in the form over on the right you will be taken to a page on TripAdvisor that shows hotels that are available for the dates that you chose.

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Finding a Loop in a Singly Linked List

Motivation

A singly linked list is a common data structure familiar to all computer scientists. A singly linked list is made of nodes where each node has a pointer to the next node (or null to end the list). A singly linked list is often used as a stack (or last in first out queue (LIFO)) because adding a new first element, removing the existing first element, and examining the first element are very fast O(1) operations.

When working with singly linked list, you are typically given a link to the first node. Common operations on a singly linked list are iterating through all the nodes, adding to the list, or deleting from the list. Algorithms for these operations generally require a well formed linked list. That is a linked list without loops or cycles in it.

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Convert a Java OutputStream to an InputStream

If you have ever programmed using Java IO, you will quickly run into a situation in which a class creates data on an OutputStream and you need to send it to another class that expects to read the data from an input stream. You'll soon be asking the question, "How do I convert an OutputStream to an InputStream?"

Nowhere in Java will you find a OutpStreamToInputStreamConverter class. Luckily, there are several ways to go about this.

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Convert a Java Writer to a Reader

If you have ever programmed using Java IO, you will quickly run into a situation in which a class creates data on a Writer and you need to send it to another class that expects to read the data from a Reader. You'll soon be asking the question, "How do I convert a Writer to a Reader?"

Nowhere in Java will you find a WriterToReaderConverter class. Luckily, there are several ways to go about this.

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Finding Comments in Source Code Using Regular Expressions

Many text editors have advanced find (and replace) features. When I'm programming, I like to use an editor with regular expression search and replace. This feature is allows one to find text based on complex patterns rather than based just on literals. Upon occasion I want to examine each of the comments in my source code and either edit them or remove them. I found that it was difficult to write a regular expression that would find C style comments (the comments that start with /* and end with */) because my text editor does not implement the "non-greedy matching" feature of regular expressions.

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