Data commit

Task/Determine-if-a-string-is-numeric/FreeBASIC/determine-if-a-string-is-numeric.basic

@@ -0,0 +1,95 @@
+' FB 1.05.0 Win64
+
+Dim Shared symbols(0 To 15) As UByte
+For i As Integer = 48 to 57
+  symbols(i - 48) = i
+Next
+For i As Integer = 97 to 102
+  symbols(i - 87) = i
+Next
+
+Const plus  As UByte = 43
+Const minus As Ubyte = 45
+Const dot   As UByte = 46
+
+Function isNumeric(s As Const String, base_ As Integer = 10) As Boolean
+  If s = "" OrElse s = "."  OrElse s = "+" OrElse s = "-" Then Return False
+  Err = 0
+
+  If base_ < 2 OrElse base_ > 16 Then
+    Err = 1000
+    Return False
+  End If
+
+  Dim t As String = LCase(s)
+
+  If (t[0] = plus) OrElse (t[0] = minus) Then
+     t = Mid(t, 2)
+  End If
+
+  If Left(t, 2) = "&h" Then
+    If base_ <> 16 Then Return False
+    t = Mid(t, 3)
+  End if
+
+  If Left(t, 2) = "&o" Then
+    If base_ <> 8 Then Return False
+    t = Mid(t, 3)
+  End if
+
+  If Left(t, 2) = "&b" Then
+    If base_ <> 2 Then Return False
+    t = Mid(t, 3)
+  End if
+
+  If Len(t) = 0 Then Return False
+  Dim As Boolean isValid, hasDot = false
+
+  For i As Integer = 0 To Len(t) - 1
+    isValid = False
+
+    For j As Integer = 0 To base_ - 1
+      If t[i] = symbols(j) Then
+        isValid = True
+        Exit For
+      End If
+      If t[i] = dot Then
+        If CInt(Not hasDot) AndAlso (base_ = 10) Then
+          hasDot = True
+          IsValid = True
+          Exit For
+        End If
+        Return False ' either more than one dot or not base 10
+      End If
+    Next j
+
+    If Not isValid Then Return False
+  Next i
+
+  Return True
+End Function
+
+Dim s As String
+s = "1234.056789"
+Print s, " (base 10) => "; isNumeric(s)
+s = "1234.56"
+Print s, " (base 7)  => "; isNumeric(s, 7)
+s = "021101"
+Print s, " (base 2)  => "; isNumeric(s, 2)
+s = "Dog"
+Print s, " (base 16) => "; isNumeric(s, 16)
+s = "Bad125"
+Print s, " (base 16) => "; isNumeric(s, 16)
+s = "-0177"
+Print s, " (base 8)  => "; isNumeric(s, 8)
+s = "+123abcd.ef"
+Print s, " (base 16) => "; isNumeric(s, 8)
+s = "54321"
+Print s, " (base 6)  => "; isNumeric(s, 6)
+s = "123xyz"
+Print s, " (base 10) => "; isNumeric(s)
+s = "xyz"
+Print s, " (base 10) => "; isNumeric(s)
+Print
+Print "Press any key to quit"
+Sleep