Testing evenness

### 6.1.11 Testing evenness

The even command tests an integer to see if it is even. (A Gaussian integer a+ib is even exactly when a and b are both even and odd otherwise.)

- even takes n, an integer.
- even(n) returns 1 if n is even and returns 0 if n is odd.

#### Examples

even(148)

1 |  |  |  |  |  |  |  |  |  |

even(149)

0 |  |  |  |  |  |  |  |  |  |

even(2+4*i)

1 |  |  |  |  |  |  |  |  |  |