Last year, I wrote about using the standard error device stderr to generate output that can’t be redirected. This technique is often used to send error messages to the console, though I noted how these messages may show up out of sync with standard output. This situation can be resolved, providing you know how to flush the stderr device buffer.
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Stop using the atoi() function! Yes, it’s a golden oldie, often my go-to function for converting strings to integers, but it’s weak. The strtol() function, on the other hand, not only converts strings to integers, it can validate input as well.
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Imagine my disappointment to learn that the atoi() function, one of the first I learned in C, is actually a macro. I’m horrified. As much as I treasure converting strings to integers, I shall survive this life-changing discovery.
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The C language lacks an exponentiation operator, which would raise a base value to a certain power. For example: 2^8, which in some programming languages is an expression to raise 2 to the 8th power. Instead, C uses the pow() function.
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Always be careful when manipulating strings! Tack on that null character, '\0', at the end of a string! And don’t worry about the C language string functions: They perform this important feature for you. But do they all?
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Say you must read 2048 bytes from a file. Which of the following fread() statements works for you: A, B, both, or neither?
A. c = fread( buffer, 2048, 1, fh);
B. c = fread( buffer, 1, 2048, fh);
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Like doing anything for a long period of time, I find myself often using the same approach to solving a programming puzzle. It’s habit. It’s tradition. And it often hinders my insight into the language.
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The fall-through effect of the switch-case structure can be extremely useful, as demonstrated in last week’s Lesson. For slicing words from a string, you can easily match multiple word separators, saving you from coding complex statements or weirdo if-else structures. But a problem arises when multiple word separators appear.
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C language keywords often used in a switch-case structure are switch, case, default, and break. Only switch and case are required. You can omit the default condition. And the break keyword is used to avoid execution falling through the structure, yet sometimes that may be a useful effect.
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The switch-case structure is the most complex decision tool in the C language. Yes, the ternary operator is more cryptic, but a proper switch-case structure involves more keywords: switch, case, default, and break. The break keyword is what I feel makes the structure most interesting.
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