gcd (ANSI and GNU Common Lisp Document)

Next: incf, Previous: exp, Up: Numbers Dictionary

#### 12.2.32 gcd [Function]

`gcd` &rest integers ⇒ greatest-common-denominator

#### Arguments and Values::

integer—an integer.

greatest-common-denominator—a non-negative integer.

#### Description::

Returns the greatest common divisor of integers. If only one integer is supplied, its absolute value is returned. If no integers are given, gcd returns `0`, which is an identity for this operation.

#### Examples::

     (gcd) ⇒  0
     (gcd 60 42) ⇒  6
     (gcd 3333 -33 101) ⇒  1
     (gcd 3333 -33 1002001) ⇒  11
     (gcd 91 -49) ⇒  7
     (gcd 63 -42 35) ⇒  7
     (gcd 5) ⇒  5
     (gcd -4) ⇒  4

#### Exceptional Situations::

Should signal an error of type type-error if any integer is not an integer.

#### See Also::

lcm

#### Notes::

For three or more arguments,

     (gcd b c ... z) ≡ (gcd (gcd a b) c ... z)