Data commit

Task/Circular-primes/FreeBASIC/circular-primes.basic

@@ -0,0 +1,31 @@
+#define floor(x) ((x*2.0-0.5) Shr 1)
+
+Function isPrime(Byval p As Integer) As Boolean
+    If p < 2 Then Return False
+    If p Mod 2 = 0 Then Return p = 2
+    If p Mod 3 = 0 Then Return p = 3
+    Dim As Integer d = 5
+    While d * d <= p
+        If p Mod d = 0 Then Return False Else d += 2
+        If p Mod d = 0 Then Return False Else d += 4
+    Wend
+    Return True
+End Function
+
+Function isCircularPrime(Byval p As Integer) As Boolean
+    Dim As Integer n = floor(Log(p)/Log(10))
+    Dim As Integer m = 10^n, q = p
+    For i As Integer = 0 To n
+        If (q < p Or Not isPrime(q)) Then Return false
+        q = (q Mod m) * 10 + floor(q / m)
+    Next i
+    Return true
+End Function
+
+Dim As Integer p = 2, dp = 1, cont = 0
+Print("Primeros 19 primos circulares:")
+While cont < 19
+    If isCircularPrime(p) Then Print p;" "; : cont += 1
+    p += dp: dp = 2
+Wend
+Sleep