Often in my code I use a variable to both fetch data and to test the data. Before using this variable, it must be initialized, lest the test act on uninitialized garbage. A clever solution is necessary to avoid this situation.
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It’s incorrect to say that the format string for the printf() function is identical to the one used in the scanf() function. Both are similar, but scanf() has one major difference.
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It’s sad but understandable that most C programmers use the scanf() function in a limited capacity. True, the function is dorky, so I accept any aversion to its use. It can also be abused to pose a security risk. Still, for “research purposes,” it’s entertaining to see how much the function can be twisted and torqued.
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One of the things I dread in my books, is foisting the scanf() function upon a beginner. I have no way around this frustration.
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Like all variables in C, arrays are declared uninitialized. They contain whatever junk already exists in memory. Initializing an array is therefore important. It can be done in one of three ways: as it’s declared, in a loop, or as it’s used in the code.
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I occasionally visit Rosetta Code to look for C language inspiration. The site offers a programming puzzle, then presents solutions in various languages. A recent challenge involved the 21 number game — but the C language had no solution!
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A switch-case structure performs a complex decision in your code, similar to a cascade of if else-if else statements. The structure works like a comparison as a whole, acting upon single values or variables. But its construction need not lack expressions.
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In last week’s Lesson, I lamented that C lacks a function to compare two floating point values based on a significant number of digits. Being a C programmer, I resolved this issue by writing a function that accomplishes this suddenly necessary task.
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From last week’s Lesson, I plowed into a BASIC programming book I worked on 35 years ago. (Yes, I’m old.) In it, substitute code was offered for commands not available in every version of BASIC. To appreciate this necessity, understand that back in those days computers weren’t file-to-file compatible, so translating programming language dialects was part of the job.
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The first part of my writing career began by updating a computer book bestseller, The BASIC Handbook. This tome served as a lexicon for the various BASIC programming language dialects, allowing users from one version of BASIC to translate and use code from another version.
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