January 2019
Intermediate to advanced
246 pages
5h 23m
English
Content preview from Programming Crystal
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Exception Handling for Faulty Input
It’s great to gather outside input for your program, but sometimes that input can create new challenges. You probably know the slogan “Garbage in, garbage out”: wrong input can corrupt all further processing. In our previous example, suppose the user enters a string such as "abc" when the program expects an integer number—a string that isn’t convertible to an integer. What happens then? Something awful: a runtime error or exception. As a professional programmer, you’ll want to avoid this at all costs.
| <= | Invalid Int8: abc (ArgumentError) |
| | 0x451477: *CallStack::unwind:Array(Pointer(Void)) at ?? |
| | 0x465a92: to_i8 at /opt/crystal/src/string.cr 358:5 |
| | ... |
You must always guard against dangerous input. The best ...
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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.
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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.