Modular inverse: Difference between revisions
→{{header|MAD}}
Line 1,858:
</syntaxhighlight>
=={{header|m4}}==
{{trans|Mercury}}
<syntaxhighlight lang="m4">
divert(-1)
# I assume non-negative arguments. The algorithm is described at
# https://en.wikipedia.org/w/index.php?title=Extended_Euclidean_algorithm&oldid=1135569411#Modular_integers
define(`inverse',`_$0(eval(`$1'), eval(`$2'))')
define(`_inverse',`_$0($2, 0, 1, $2, $1)')
define(`__inverse',
`dnl n = $1, t = $2, newt = $3, r = $4, newr = $5
ifelse(eval($5 != 0), 1, `$0($1, $3,
eval($2 - (($4 / $5) * $3)),
$5,eval($4 % $5))',
eval($4 > 1), 1, `no inverse',
eval($2 < 0), 1, eval($2 + $1),
$2)')
divert`'dnl
inverse(42, 2017)
</syntaxhighlight>
{{out}}
<pre>$ m4 modular-inverse-task.m4
1969</pre>
=={{header|MAD}}==
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