14 lines
574 B
Plaintext
14 lines
574 B
Plaintext
;Task:
|
|
Test whether an integer is even or odd.
|
|
|
|
There is more than one way to solve this task:
|
|
|
|
* Use the even and odd predicates, if the language provides them.
|
|
* Check the least significant digit. With binary integers, ''i [[bitwise operations|bitwise-and]] 1'' equals 0 [[wikt:iff|iff]] ''i'' is even, or equals 1 iff ''i'' is odd.
|
|
* Divide ''i'' by 2. The remainder equals 0 iff ''i'' is even. The remainder equals +1 or -1 iff ''i'' is odd.
|
|
* Use modular congruences:
|
|
** ''i'' ≡ 0 (mod 2) iff ''i'' is even.
|
|
** ''i'' ≡ 1 (mod 2) iff ''i'' is odd.
|
|
<br><br>
|
|
|