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Determine if a string is numeric: Difference between revisions
Determine if a string is numeric (view source)
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{{task}}
Demonstrates how to implement a custom IsNumeric method in other .NET/Mono languages that do not wish to reference the Microsoft.VisualBasic.dll assembly.
==[[Ada]]==
[[Category:Ada]]
The first file is the package interface containing the declaration of the Is_Numeric function.
package Numeric_Tests is
function Is_Numeric(Item : in String) return Boolean;
end Numeric_Tests;
The second file is the package body containing the implementation of the Is_Numeric function.
package body Numeric_Tests is
----------------
-- Is_Numeric --
----------------
function Is_Numeric (Item : in String) return Boolean is
Result : Boolean := True;
begin
declare
Int : Integer;
begin
Int := Integer'Value(Item);
exception
when others =>
Result := False;
end;
if Result = False then
declare
Real : Float;
begin
Real := Float'Value(Item);
Result := True;
exception
when others =>
null;
end;
end if;
return Result;
end Is_Numeric;
end Numeric_Tests;
The last file shows how the Is_Numeric function can be called.
with Ada.Text_Io; use Ada.Text_Io;
with Numeric_Tests; use Numeric_Tests;
procedure Isnumeric_Test is
S1 : String := "152";
S2 : String := "-3.1415926";
S3 : String := "Foo123";
begin
Put_Line(S1 & " results in " & Boolean'Image(Is_Numeric(S1)));
Put_Line(S2 & " results in " & Boolean'Image(Is_Numeric(S2)));
Put_Line(S3 & " results in " & Boolean'Image(Is_Numeric(S3)));
end Isnumeric_Test;
The output of the program above is:
152 results in TRUE
-3.1415926 results in TRUE
Foo123 results in FALSE
==[[C sharp|C#]]==
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