Data commit

Task/Chowla-numbers/FreeBASIC/chowla-numbers.basic

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+' Chowla_numbers
+
+#include "string.bi"
+
+Dim Shared As Long limite
+limite = 10000000
+Dim Shared As Boolean c(limite)
+Dim As Long count, topenumprimo, a
+count = 1
+topenumprimo = 100
+Dim As Longint p, k, kk, limitenumperfect
+limitenumperfect = 35000000
+k = 2: kk = 3
+
+Declare Function chowla(Byval n As Longint) As Longint
+Declare Sub sieve(Byval limite As Long, c() As Boolean)
+
+Function chowla(Byval n As Longint) As Longint
+    Dim As Long i, j, r
+    i = 2
+    Do While i * i <= n
+        j = n \ i
+        If n Mod i = 0 Then
+            r += i
+            If i <> j Then r += j
+        End If
+        i += 1
+    Loop
+    chowla = r
+End Function
+
+Sub sieve(Byval limite As Long, c() As Boolean)
+    Dim As Long i, j
+    Redim As Boolean c(limite - 1)
+    i = 3
+    Do While i * 3 < limite
+        If Not c(i) Then
+            If chowla(i) = false Then
+                j = 3 * i
+                Do While j < limite
+                    c(j) = true
+                    j += 2 * i
+                Loop
+            End If
+        End If
+        i += 2
+    Loop
+End Sub
+
+Print "Chowla numbers"
+For a = 1 To 37
+    Print "chowla(" & Trim(Str(a)) & ") = " & Trim(Str(chowla(a)))
+Next a
+
+' Si chowla(n) = falso and n > 1 Entonces n es primo
+Print: Print "Contando los numeros primos hasta: "
+sieve(limite, c())
+For a = 3 To limite - 1 Step 2
+    If Not c(a) Then count += 1
+    If a = topenumprimo - 1 Then
+        Print Using "########## hay"; topenumprimo;
+        Print count
+        topenumprimo *= 10
+    End If
+Next a
+
+' Si chowla(n) = n - 1 and n > 1 Entonces n es un número perfecto
+Print: Print "Buscando numeros perfectos... "
+count = 0
+Do
+    p = k * kk : If p > limitenumperfect Then Exit Do
+    If chowla(p) = p - 1 Then
+        Print Using "##########,# es un numero perfecto"; p
+        count += 1
+    End If
+    k = kk + 1 : kk += k
+Loop
+Print: Print "Hay " & count & " numeros perfectos <= " & Format(limitenumperfect, "###############################,#")
+
+Print: Print "Pulsa una tecla para salir"
+Sleep
+End