Data update

Task/Additive-primes/S-BASIC/additive-primes.basic

@@ -0,0 +1,55 @@
+$constant true = 0FFFFH
+$constant false = 0
+$constant limit = 500
+
+function sum.of.digits(n = integer) = integer
+   var i, sum = integer
+   var s = string
+   var ch = char
+   s = str$(n)
+   sum = 0
+   for i = 2 to len(s)
+      ch = mid(s,i,1)
+      sum = sum + (ch - '0')
+   next i
+end = sum
+
+function mod(n, m = integer) = integer
+end = n - (n / m) * m
+
+comment
+  build a table of prime numbers using
+  the classic sieve of Erathosthenes
+end
+dim integer prime(limit)
+var i, j, count = integer
+prime(1) = false
+for i = 2 to limit
+  prime(i) = true
+next i
+rem - strike out multiples of each prime found
+for i = 2 to sqr(limit)
+  if prime(i) then
+    begin
+      for j = i + i to limit step i
+        prime(j) = false
+      next j
+    end
+next i
+
+rem - use the table for the search
+print "Searching up to"; limit; " for additive primes"
+count = 0
+for i = 2 to limit
+  if prime(i) then
+    if prime(sum.of.digits(i)) then
+      begin
+        print using "###  "; i;
+        count = count + 1
+        if mod(count, 10) = 0 then print
+      end
+next i
+print
+print count;" were found"
+
+end