January 2019
Intermediate to advanced
246 pages
5h 23m
English
Content preview from Programming Crystal
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Chapter 2: Crystal Foundations
Your Turn 1
| | 12 + 12 # => 24 |
| | |
| | "12 + 12" # => 12 + 12 |
| | |
| | "12" + "12" # => 1212 |
| | |
| | "I" * 5 # => "IIIII" |
The following statements give compilation errors:
| | '12' + '12' # => unterminated char literal, use double quotes for strings |
| | |
| | 5 * "I" # => no overload matches 'Int32#*' with type String |
| | |
| | "12" + 12 # => no overload matches 'String#+' with type Int32 |
| | |
| | "2" * "5" # => no overload matches 'String#*' with type String |
Your Turn 2
delete.cr
Your Turn 3
empty.cr
Your Turn 4
99_bottles_of_beer.cr
Your Turn 5
method.cr
Your Turn 6
a. union.cr
b. class.cr
Your Turn 7
For 500,000 fibers, I got:
$ crystal build fibers.cr --release
$ time ./fibers # => real 0m5.242s
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.