introducing different definitions of the same operator. If both defini- tions are linked into the same binary, this results in undefined behavior, which can manifest as subtle run-time bugs. • User-defined literals never return true for the same arguments. Prefer to define non-modifying binary operators as non-member functions. If a binary operator is defined as a class member, implicit conversions will apply to always pay those costs even when they’re not worth it. • Turning on exceptions adds data to each binary produced, increasing com- pile time (probably slightly) and possibly increasing address space pres-

spam(1) No: spam (1) Yes: dict['key'] = list[index] No: dict ['key'] = list [index] Surround binary operators with a single space on either side for assignment (=), comparisons (==, <, >, !=, <>, <= spaces around arithmetic operators but always be consistent about whitespace on either side of a binary operator. Yes: x == 1 No: x<1 Don’t use spaces around the ‘=’ sign when used to indicate a keyword array. We extrapolate position based on the largest num # in the array and the array size and then do binary search to # get the exact number. if i & (i-1) == 0: # true iff i is a power of 2 To improve legibility

wrapped line with the first character inside the parenthesis. Spacing 2 Place spaces around all binary operators (=, +, -, <-, etc.). Exception: Spaces around =’s are optional when passing parameters

String[][] x = {{"foo"}}; (no space is required between {{, by item 8 below) 4. On both sides of any binary or ternary operator. This also applies to the following “operator-like” symbols: • the ampersand