Exercise 5-18. Make the basic dcl program recover from input errors. K&R’s dcl program (Section 5.12) parses C declarations into English. It calls error() which prints a message and then exits — making it useless for batch input. The fix: on error, skip to the next newline and try to continue. This requires turning dcl‘s …
Exercise 5-17. Add a field-handling capability, so sorting may be done on fields within lines, each field sorted according to an independent set of options. (The index for this book was sorted with -df for the index category and -n for the page numbers.) Fields are whitespace-delimited columns. The syntax -k<field>[flags] selects a 1-based field …
Exercise 5-15. Add the option -f to fold upper and lower case together, so that case distinctions are not made during sorting; for example, a and A compare equal. Add a fold flag. When set, the comparison function converts both characters to lowercase before comparing. The key: don’t modify the strings themselves — do the …
Exercise 5-16. Add the -d (directory order) option, which makes comparisons only on letters, numbers and blanks. Make sure it works in conjunction with -f. Directory order ignores punctuation and control characters — only alphanumeric characters and spaces are considered. The comparison function skips non-directory characters in both strings simultaneously, then compares the next significant …
C Program to demonstrate the strtok function.strtok function breaks pointed by the string1 into sequence of tokens, which are sequences of contiguous characters separated by any of the characters that are part of delimiters.In this program we split the test_string, i,e “string to split up ” tostringtosplitupRead more about C Programming Language . /************************************************************ You …
Exercise 5-14. Modify the sort program to handle a -r flag, which indicates sorting in reverse (decreasing) order. Be sure that -r works with -n. The K&R sort from Section 5.11 calls qsort with a comparison function strcmp. Adding -r requires the comparison function to negate its result. The cleanest approach: add a global flag …