A filter is a command line tool that takes input, modifies it, and generates output. This month’s Exercise is to create such a filter, one that takes text input and spews it out one word at a time.
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\nDon’t fret! I’m not asking you to create a word wrap filter, which was mulled over during most of May’s Lessons. Instead, this month’s Exercise is to create a filter that reads standard input up until a white space character is encountered. At that point, the word is displayed on a line by itself.<\/p>\n
For example, for the input Because I’m feeling generous, my simple solution to this problem is presented below.<\/p>\n Don’t think you’re getting off easy this month, however. That’s because my simple solution overlooks two distinct problems. If you can already see the problems, then good for you<\/em>!<\/p>\n The first problem is an issue I call bounds checking<\/em>, although the specific term applied to the sample code would be buffer overflow<\/em>. Therefore your first task is to re-write the code so that the And, no, the solution is not just to make the The second problem involves a situation where perhaps more than one white space is encountered in a row. For example, the input And not:<\/p>\n Fix with my prototype code (above), or craft new code, so that these two situations are avoided.<\/p>\n Please eschew your desire to peek ahead at my solution before you attempt to code your own. Further, if you’re feeling up to it, consider coding a solution by using pointers. Heck, toss in a malloc()<\/em> function in there. Give yourself a challenge!<\/p>\n Remember: My solutions demonstrate only one way to solve the problem. In programming, many approaches are possible, some can be more elegant or cryptic, but no one correct answer exists.<\/p>\n Exercise Solution<\/a><\/p>\n Exercise Solution with Pointers<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" See whether you can code an I\/O filter that chops text up into single words. Continue reading We the People of the United States<\/code> the code would generate the following output:<\/p>\nWe\r\nthe\r\nPeople\r\nof\r\nthe\r\nUnited\r\nStates<\/code><\/pre>\n\r\n#include <stdio.h>\r\n#include <ctype.h>\r\n\r\n#define SIZE 80\r\n\r\nint main()\r\n{\r\n char buffer[SIZE];\r\n int index,c;\r\n\r\n \/* initalize variables *\/<\/span>\r\n c = 1; \/* avoid random EOF *\/<\/span>\r\n index = 0;\r\n buffer[index] = '\\0';\r\n\r\n \/* process standard input *\/<\/span>\r\n while(c != EOF)\r\n {\r\n c = getchar();\r\n if( isspace(c) ) \/* whitespace found *\/<\/span>\r\n {\r\n buffer[index] = '\\0'; \/* cap the string *\/<\/span>\r\n puts(buffer); \/* display w\/newline *\/<\/span>\r\n index = 0; \/* reset index *\/<\/span>\r\n }\r\n else \/* keep filling the buffer *\/<\/span>\r\n {\r\n buffer[index] = c;\r\n index++;\r\n }\r\n }\r\n\r\n return(0);\r\n}<\/pre>\nbuffer[]<\/code> doesn’t keep filling up with characters after its SIZE<\/code> is encountered.<\/p>\nSIZE<\/code> constant larger.<\/p>\nThis is an oddly formatted sentence<\/code> still needs to be output as<\/p>\nThis\r\nis\r\nan\r\noddly\r\nformatted\r\nsentence<\/code><\/pre>\nThis\r\nis\r\n\r\nan\r\n\r\n\r\noddly\r\n\r\nformatted\r\n\r\nsentence<\/code><\/pre>\n