Data commit

Task/Additive-primes/ALGOL-68/additive-primes.alg

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+BEGIN # find additive primes - primes whose digit sum is also prime #
+    # sieve the primes to max prime #
+    PR read "primes.incl.a68" PR
+    []BOOL prime = PRIMESIEVE 499;
+    # find the additive primes #
+    INT additive count := 0;
+    FOR n TO UPB prime DO
+        IF prime[ n ] THEN
+            # have a prime #
+            INT digit sum := 0;
+            INT v         := n;
+            WHILE v > 0 DO
+                digit sum +:= v MOD 10;
+                v OVERAB 10
+            OD;
+            IF prime( digit sum ) THEN
+                # the digit sum is prime #
+                print( ( " ", whole( n, -3 ) ) );
+                IF ( additive count +:= 1 ) MOD 20 = 0 THEN print( ( newline ) ) FI
+            FI
+        FI
+    OD;
+    print( ( newline, "Found ", whole( additive count, 0 ), " additive primes below ", whole( UPB prime + 1, 0 ), newline ) )
+END