Additive primes: Difference between revisions

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@@ Line 1,133: / Line 1,133: @@
 359 373 379 397 401 409 421 443 449
 463 467 487
+</pre>
+=={{header|Swift}}==
+<lang swift>import Foundation
+func isPrime(_ n: Int) -> Bool {
+    if n < 2 {
+        return false
+    }
+    if n % 2 == 0 {
+        return n == 2
+    }
+    if n % 3 == 0 {
+        return n == 3
+    }
+    var p = 5
+    while p * p <= n {
+        if n % p == 0 {
+            return false
+        }
+        p += 2
+        if n % p == 0 {
+            return false
+        }
+        p += 4
+    }
+    return true
+}
+func digitSum(_ num: Int) -> Int {
+    var sum = 0
+    var n = num
+    while n > 0 {
+        sum += n % 10
+        n /= 10
+    }
+    return sum
+}
+let limit = 500
+print("Additive primes less than \(limit):")
+var count = 0
+for n in 1..<limit {
+    if isPrime(digitSum(n)) && isPrime(n) {
+        count += 1
+        print(String(format: "%3d", n), terminator: count % 10 == 0 ? "\n" : " ")
+    }
+}
+print("\n\(count) additive primes found.")</lang>
+{{out}}
+<pre>
+Additive primes less than 500:
+3   5   7  11  23  29  41  43  47
+67  83  89 101 113 131 137 139 151
+173 179 191 193 197 199 223 227 229
+263 269 281 283 311 313 317 331 337
+359 373 379 397 401 409 421 443 449
+463 467 487
+additive primes found.
 </pre>