CLHS: Function GCD

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Function GCD

Syntax:

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

Side Effects: None.

Affected By: None.

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)

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