Exercise 7-9. Functions like isupper can be implemented to save space or to save time. Explore both possibilities. Standard library character-classification functions like isupper are typically implemented as macros. There are two design axes: Save time: use a precomputed lookup table — one array access, no branches, O(1) at maximum cache efficiency Save space: use …
Exercise 7-8. Write a program to print a set of files, starting each new file on a new page, with a title and a running page count for each file. Print each file with a header line (filename + page number) at the top of every page. A page is LINES_PER_PAGE lines. When a page …
Exercise 7-7. Modify the pattern finding program of Chapter 5 to take its input from a set of named files or, if no files are named, from the standard input. Should the file name be printed when a match is found? Yes — when searching multiple files the filename should prefix each matching line (the …
Exercise 7-6. Write a program to compare two files, printing the first line where they differ. Open both files, read them line by line in parallel, and compare. When a differing line is found, print both versions with a line number and exit. Also handle the case where one file is longer than the other. …
Exercise 7-5. Rewrite the postfix calculator of Chapter 4 to use scanf and/or sscanf to do the input and number conversion. The original Chapter 4 calculator used a custom getop() that read characters one at a time with getch/ungetch to recognise numbers vs operators. With scanf we replace that with a simpler approach: read one …
Exercise 7-4. Write a private version of scanf analogous to the private printf described in this section. Like minprintf, minscanf parses a format string and uses va_list to accept a variable number of pointer arguments. It reads from stdin and dispatches to the appropriate conversion — using scanf itself with a constructed sub-format string, so …