Data commit

Task/Twin-primes/Visual-Basic/twin-primes.vb

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+Function IsPrime(x As Long) As Boolean
+    Dim i As Long
+    If x Mod 2 = 0 Then
+        Exit Function
+    Else
+        For i = 3 To Int(Sqr(x)) Step 2
+            If x Mod i = 0 Then Exit Function
+        Next i
+    End If
+    IsPrime = True
+End Function
+
+Function TwinPrimePairs(max As Long) As Long
+    Dim p1 As Boolean, p2 As Boolean, count As Long, i As Long
+    p2 = True
+    For i = 5 To max Step 2
+        p1 = p2
+        p2 = IsPrime(i)
+        If p1 And p2 Then count = count + 1
+    Next i
+    TwinPrimePairs = count
+End Function
+
+Sub Test(x As Long)
+    Debug.Print "Twin prime pairs below" + Str(x) + ":" + Str(TwinPrimePairs(x))
+End Sub
+
+Sub Main()
+    Test 10
+    Test 100
+    Test 1000
+    Test 10000
+    Test 100000
+    Test 1000000
+    Test 10000000
+End Sub