As you might already know, the C language lacks plenty o’ functions readily available in other programming languages. Many of these functions, or “methods,” deal with strings. Though C includes a few basic string functions in its library, the C Lords have determined that when you need another such function, you must code it yourself. As a reminder, whitespace characters include space, newline, and tab. The POSIX standard also adds form-feed ( Below is a code skeleton to help get you started. This code runs, but it’s missing the trim()<\/em> function and the statements to call the function and output the trimmed strings.<\/p>\n The skeleton includes an array You can see that I don’t prototype the trim(<\/em>) function, so its behavior is truly at your discretion.<\/p>\n Here is sample output from my solution:<\/p>\n I can think of multiple ways to code a trim()<\/em> function, but don’t overthink things! As a suggestion, I recommend tackling the problem one step at a time.<\/p>\n Please try this exercise on your own before you peek at my solution<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" Time to test your skills and code a common string function not available in the standard C library. Continue reading
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\nThe topic for this month’s Exercise is to craft a trim()<\/em> function, which is one of those capabilities present in other programming languages but not directly in C. What this function does is to remove whitespace characters from both ends of a string.<\/p>\n\\f<\/code>), carriage return (\\r<\/code>), and vertical tab (\\v<\/code>).<\/p>\n2026_04_01-Lesson.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n\r\n\/*\r\n put the trim() function here\r\n *\/<\/span>\r\n\r\nint main()\r\n{\r\n char *sample[] = {\r\n \" one \",\r\n \"\\ttwo\\n\",\r\n \"\",\r\n \" \",\r\n \"a\",\r\n \" x \",\r\n NULL,\r\n \" \\t three \\n\",\r\n \"four\",\r\n \" five\",\r\n \"six \",\r\n \" seven eight \"\r\n };\r\n int size,x;\r\n\r\n \/* obtain array size *\/<\/span>\r\n size = sizeof(sample)\/sizeof(sample[0]);\r\n\r\n \/* output trimmed strings *\/<\/span>\r\n for( x=0; x<size; x++ )\r\n {\r\n \/* output string\r\n and trimmed string *\/<\/span>\r\n }\r\n\r\n return 0;\r\n}<\/pre>\nsample[]<\/code> that contains a slew of sample strings to trim. The strings represent a variety of possibilities such as an empty string, a string with only spaces, and NULL. These items are included because your trim()<\/em> function solution must account for everything!<\/p>\n' one ' => 'one'\r\n' two\r\n' => 'two'\r\n'' => ''\r\n' ' => ''\r\n'a' => 'a'\r\n' x ' => 'x'\r\n'(null)' => Bad string\r\n' three\r\n' => 'three'\r\n'four' => 'four'\r\n' five' => 'five'\r\n'six ' => 'six'\r\n' seven eight ' => 'seven eight'<\/pre>\n