Data commit

Task/Additive-primes/Nim/additive-primes.nim

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+import math, strutils
+
+const N = 499
+
+# Sieve of Erathostenes.
+var composite: array[2..N, bool]  # Initialized to false, ie. prime.
+
+for n in 2..sqrt(N.toFloat).int:
+  if not composite[n]:
+    for k in countup(n * n, N, n):
+      composite[k] = true
+
+
+func digitSum(n: Positive): Natural =
+  ## Compute sum of digits.
+  var n = n.int
+  while n != 0:
+    result += n mod 10
+    n = n div 10
+
+
+echo "Additive primes less than 500:"
+var count = 0
+for n in 2..N:
+  if not composite[n] and not composite[digitSum(n)]:
+    inc count
+    stdout.write ($n).align(3)
+    stdout.write if count mod 10 == 0: '\n' else: ' '
+echo()
+
+echo "\nNumber of additive primes found: ", count