RosettaCodeData/Task/Evaluate-binomial-coefficients/BCPL/evaluate-binomial-coefficie...

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GET "libhdr"
LET choose(n, k) =
~(0 <= k <= n) -> 0,
2*k > n -> binomial(n, n - k),
binomial(n, k)
AND binomial(n, k) =
k = 0 -> 1,
binomial(n, k - 1) * (n - k + 1) / k
LET start() = VALOF {
LET n, k = ?, ?
LET argv = VEC 20
LET sz = ?
sz := rdargs("n/a/n/p,k/a/n/p", argv, 20)
UNLESS sz ~= 0 RESULTIS 1
n := !argv!0
k := !argv!1
writef("%d choose %d = %d *n", n, k, choose(n, k))
RESULTIS 0
}