Join David Powers for an in-depth discussion in this video Finding all possible combinations, part of Code Clinic: PHP.
- In the problem zero three folder of my testing site,…I've created a file called queens dot php.…You can find this in the exercise files…for this video.…It contains some simple code to keep track…of how long the script takes to execute…and defines a constant called board size…and sets its value to eight.…That's the size of the chessboard.…We know that two queens can never be in the same…row or column, so we can use a loop to represent…the eight rows, each of which will contain…a queen in a different column.…
So let's have that loop.…We'll initialize row at zero.…We'll use the board size to control the loop,…and increment row each time we go through the loop.…Inside there we'll create an array called layout.…We'll give it the index of row, and then assign…the value of one, and then use the bit wise…shift left operator and the value of row.…
So this will generate binary numbers that shift…the bits the same number of places as the value…of the counter row.…The first time the loop runs row is zero,…so no bits are moved.…
David introduces challenges and provides an overview of his solutions in PHP. Challenges include topics such as statistical analysis, searching directories for images, and accessing peripheral devices.
Visit other courses in the series to see how to solve the exact same challenges in languages like C#, C++, Java, Python, and Ruby.
Skill Level Intermediate
Q: I'm encountering script errors message with the prime_dates.php file used in the "Priming the date_record column" movie in this course. How can I resolve these errors?
A: To avoid script errors, use bindValue() instead of bindParam() in
Line 9 of the prime_dates.php file. You can also download the latest
copy of the exercise files, which corrects this issue for you. For a
more in-depth explanation of the difference between bindValue() and
bindParam(), check out the "Binding input and output values" video (http://www.lynda.com/PHP-
Q: Why can't I access the Lake Pend Orielle site (http://lpo.dt.navy.mil)?
A: The Lake Pend Orielle site is not accessible in some geographical areas. We have contacted the owner of the server to try to resolve this issue.
Q: I am unable to access the Lake Pend Oreille data from outside the U.S.
A: A static copy of this data is provided here for lynda.com members outside of the U.S
Problem One: Statistical Analysis
Problem Two: Image Analysis
Problem Three: Eight Queens
Problem Four: Accessing Peripherals
Problem Five: Recursion and Directories
Problem Six: Building the Web
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