integer-log10 ( x -- n )
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Vocabulary
math.functions

Inputs

x	a positive rational number

Outputs

n	an integer

Word description
Outputs the largest integer n such that 10^n is less than or equal to x.

Errors
Throws an error if x is zero or negative.

Examples

USING: prettyprint math.functions sequences ; { 5 99 100 101 100000000000000000000 100+1/2 1/100 } [ integer-log10 ] map .
{ 0 1 2 2 20 2 -2 }

Definition

USING: math math.functions.private ;

IN: math.functions

: integer-log10 ( x -- n ) assert-positive (integer-log10) ;
    inline