- floor xprocedure
- ceiling xprocedure
- truncate xprocedure
- round xprocedure
These procedures return integers. Floor returns the largest integer not larger than x. Ceiling returns the smallest integer not smaller than x. Truncate returns the integer closest to x whose absolute value is not larger than the absolute value of x. Round returns the closest integer to x, rounding to even when x is halfway between two integers.
Rationale: Round rounds to even for consistency with the default rounding mode specified by the IEEE floating point standard.
Note: If the argument to one of these procedures is inexact, then the result will also be inexact. If an exact value is needed, the result should be passed to the inexact->exact procedure.
(floor -4.3) ===> -5.0 (ceiling -4.3) ===> -4.0 (truncate -4.3) ===> -4.0 (round -4.3) ===> -4.0 (floor 3.5) ===> 3.0 (ceiling 3.5) ===> 4.0 (truncate 3.5) ===> 3.0 (round 3.5) ===> 4.0 ; inexact (round 7/2) ===> 4 ; exact (round 7) ===> 7