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Practice of Programming - Style

I picked up The Practice of Programming by the great masters, Kernighan and Pike. I’m planning to find time to read a chapter every day and then note down the outline here. And then every month, wherever I’m, come back and browse through it!

Style

1. Names
   • Use descriptive names for globals, short names for locals
   • Be consistent
   • Use active names for functions
   • Be accurate
2. Expressions and statements
   • Indent to show structure
   • Use the natural form for expressions
   • Parenthesize to resolve ambiguity
   • Break up complex expressions
   • Be clear
   • Be careful with side effects
3. Consistency and idioms
   • Use a consistent indentation and brace style
   • Use idioms for consistency
   • Use else-ifs for multi-way decisions
4. Functions macros
   • Avoid function macros
   • Parenthesize the macro body and arguments
5. Magic numbers
   • Give names to magic numbers
   • Define numbers as constants, not macros
   • Use character constants, not integers
   • Use the language to calculate the size of an object
6. Comments
   • Don’t belabor the obvious
   • Comment functions and global data
   • Don’t comment bad code, rewrite it
   • Don’t contradict the code
   • Clarify, don’t confuse

Gem

Can you figure out what is wrong with this macro in C?
#define isupper(c) ((c) >= 'A' && (c) <= 'Z')

Try calling it like while (isupper(c = getchar()) and you will know what is wrong! Hint - instead of it being a macro, write it as a function.

Or, use a stylish language that simply won’t require you to waste time on making readable code.