K&R in Plan 9 C

These pages chronicle my (abandoned as of Jan 2022) journey through Brian Kernighan and Dennis Ritchie’s The C Programming Language (Second Edition) [PDF] — but rendering the example programs and exercises in the Plan 9 implementation (“dialect”) of C rather than in the book’s ANSI C.

Plan 9 C uses a different standard library from ANSI C as well as different style conventions [1]. Minor differences are therefore visible in every program here. A few of these programs demonstrate major differences (mainly having to do with core input and output functions); these programs are indicated in bold.

One disclaimer: These programs represent only the best efforts of a hobbyist. There may be better ways to implement the Plan 9 standard library than I have found, and for all I know, some of my solutions may do things the “wrong” way. Beware!

–tweedy

[1]: See P. Gagliardi, “C Programming in Plan 9 from Bell Labs”; style(6).

Chapter 1

Programs

• “hello, world ☺” [p. 7]
• Fahrenheit-Celsius table [p. 9]
• Fahrenheit-Celsius table; floating-point version [p. 12]
• File Copying [p. 16]
• Count Characters [p. 18]
• Count Lines [p. 19]
• Word Counting [p. 20]
• Count Digits, White Space, Others [p. 22]
• Power [p. 24]
• Longest Line [p. 29]
• Longest Line (external variables) [p. 32]

Exercises

• Exercise 1.1: hello, world ☺ [p. 8]
• Exercise 1.2: Print Escape Characters [p. 8]
• Exercise 1.3: Temperature Table with Header [p. 13]
• Exercise 1.4: Celsius to Fahrenheit Table [p. 13]
• Exercise 1.5: Temperature Table (reverse) [p. 14]
• Exercise 1.6: Verify EOF [p. 17]
• Exercise 1.7: Print Value of EOF [p. 17]
• Exercise 1.8: Count Blanks, Tabs, and Newlines [p. 20]
• Exercise 1.9: Replace multiple blanks with a single [p. 20]
• Exercise 1.10: Escape Tabs, Backspaces, and Backslashes [p. 20]
• Exercise 1.12: Print each word on a new line [p. 20]
• Exercise 1.13: Histogram of Word Lengths [p. 24]
• Exercise 1.14: Histogram of Characters [p. 24]
• Exercise 1.15: Temperature Conversion (with function) [p. 27]
• Exercise 1.16: Longest Line (accept long input) [p. 30]
• Exercise 1.17: Print Lines Longer than 80 Characters [p. 31]
• Exercise 1.18: Remove Trailing Blanks [p. 31]
• Exercise 1.19: Reverse Lines [p. 31]
• Exercise 1.20: Detab [p. 34]
• Exercise 1.21: Entab [p. 34]
• Exercise 1.22: Fold Lines [p. 34]
• Exercise 1.23: Decomment [p. 34]
• Exercise 1.24: Syntax Error Checker [p. 34]