Data commit

Task/Additive-primes/Dart/additive-primes.dart

@@ -0,0 +1,29 @@
+import 'dart:math';
+
+void main() {
+  const limit = 500;
+  print('Additive primes less than $limit :');
+  int count = 0;
+  for (int n = 1; n < limit; ++n) {
+    if (isPrime(digit_sum(n)) && isPrime(n)) {
+      print('   $n');
+      ++count;
+    }
+  }
+  print('$count additive primes found.');
+}
+
+bool isPrime(int n) {
+  if (n <= 1) return false;
+  if (n == 2) return true;
+  for (int i = 2; i <= sqrt(n); ++i) {
+    if (n % i == 0) return false;
+  }
+  return true;
+}
+
+int digit_sum(int n) {
+  int sum = 0;
+  for (int m = n; m > 0; m ~/= 10) sum += m % 10;
+  return sum;
+}