Exercise 7-2. Write a program that will print arbitrary input in a sensible way. As a minimum it should print non-graphic characters in octal or hex (according to local custom), and fold long lines. The rules: Printable characters (isprint) pass through as-is \n resets the column counter; \t and other non-printable characters are shown as …
Exercise 6-6. Implement a simple version of the #define processor (i.e., no arguments) suitable for use with C programs, based on the routines of this section. You may also find getch and ungetch useful. The processor reads C source line by line. When it sees #define NAME replacement it calls install from the hash table …
Exercise 6-5. Write a function undef that will remove a name and definition from the table maintained by lookup and install. K&R Section 6.6 presents a hash table with separate chaining: an array of HASHSIZE buckets, each being the head of a linked list of struct nlist nodes. install adds a name/definition pair; lookup finds …
Exercise 6-4. Write a program that prints the distinct words in its input sorted into decreasing order of frequency of occurrence. Precede each word by its count. Count words using K&R’s binary tree (Section 6.5), then collect all nodes into an array and sort by count descending using qsort. The key insight: the tree is …
Exercise 6-2. Write a program that reads a C program and prints in alphabetical order each group of variable names that are identical in the first 6 characters, but different somewhere thereafter. Don’t count words within strings and comments. Make 6 a parameter. The strategy: Use the improved getword from Exercise 6-1 to read identifiers, …
Exercise 6-1. Our version of getword does not properly handle underscores, string constants, comments, or preprocessor control lines. Write a better version. K&R’s getword from Section 6.3 reads the next identifier or non-alphabetic character from input, but has four gaps: Underscores: valid in C identifiers (_var, size_t) but the original checks only isalpha String constants: …