I don’t think I’ve ever used the return value from a printf() statement. Yes, the function has an int return value, which is the number of characters output. This value can be difficult to guess.
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In C programming, variables declared within a function are local to the function. Specifically, they’re the auto storage class, the default. External, or global, variables are defined outside of a function declaration and are of the extern storage class. These variables are available to all functions. But the scope within a function can also be limited, depending on where the variable is declared.
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As I wrote in last week’s Lesson, the system() function can’t be used in Linux to obtain a program’s return value. Instead, you must use one of the execl() family of functions. Further, this function must be spawned as a child process. This task involves using the fork() and wait() functions.
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At the end of the main() function, a return statement must surrender an integer value to the operating system. Does a higher value please the OS? Is it offended by zero? What exactly happens with the value returned when your program is done?
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I screwed up some code in a most delightful manner, all without knowing what I did. In fact, it was a student who ran my less-than-brilliant code and discovered the obvious flaw. But I was clueless.
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The strcasecmp() function isn’t part of the standard C library, though many compilers feature it. As having the function is handy, I wrote about crafting your own version back in 2019. Alas, that implementation is flawed.
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Any mortal programmer would have stopped with last week’s Lesson, where a tally of unique and duplicate words is output. This is the desired result, right? Yes, but it’s an un-orderly list.
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The next step in the unique words program is to tally the count of each word. From last week’s Lesson, the word list is sorted, which makes the task of counting duplicates easy.
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In our last episode, the unique words code is able to parse and list individual words in the buffer. To find unique and duplicate words, the next step is to sort the list.
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From last week’s Lesson, the text in a buffer is parsed, creating pointers to each word in the string. Alas, the addresses of these words (the pointers) aren’t saved, which is stupid. To handle the job, and to keep the Unique Words project moving forward, a dynamic array of pointers must be allocated.
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