# Calculates the greatest common divisor of two natural numbers a and b based on the Euclidean Algorithm

### Description

The function ggT calculates the greatest common divisor of two
natural numbers. In this package it is called by the function
`kgV`

which calculates the least common multiple of
two natural numbers. The latter is needed by the function
`zykloid`

and by the function `npeaks`

which calculates the number of peaks (or loops) a cycloid has.
As the greatest common divisor might be useful for other
purposes, the function ggT is accessible to external use in this
package.

### Usage

1 | ```
ggT(a, b)
``` |

### Arguments

`a` |
A natural number (integer value > 0) |

`b` |
A natural number (integer value > 0) |

### Value

A natural number if *a* and *b* are natural numbers. In any other
case, the function returns NA.

### Author(s)

Peter Biber

### References

Bronstein IN, Semendjaev KA, Musiol G, Muehlig H (2001): Taschenbuch der
Mathematik, 5th Edition, Verlag Harri Deutsch, 1186 p. (p. 333)

http://en.wikipedia.org/wiki/Euclidean_algorithm

### See Also

`kgV`

, `npeaks`

### Examples

1 2 3 4 5 6 7 8 |