# floor function

The**floor function**of

*x*, historically called the

**greatest integer function**, is the greatest integer less than or equal to

*x*. This function is sometimes written [x], but is best written (a notation that was suggested by Iverson in 1962) to differentiate it from the ceiling function.

Examples: [3.14159]=3, [-3.14159]=-4,
and [log(*n*)/log(10)]+1 is the number of digits in the decimal expansion of the positive integer *n*.

**See Also:** CeilingFunction

**References:**

- Iverson62
K. E. Iverson,A programming language, John Wiley \& Sons, 1962.MR 26:913

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