Integer? float? confused...

Integer? float? confused...

[WM]

I have written a program to calculate Sin. The compiler(AdaGIDE 6.23) said:
"expected type standard.float", why? Please piont out errors, Thanks.

with Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
use Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;

procedure sin is
   sin_result : float;
   i : integer;
   function Calc_Sin (Num : Integer) return float is
      begin
         Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;
         return Sin_Result;
   end Calc_Sin;

begin

put("input int: ");
get(i);
Sin_Result := Calc_Sin(Num=>i);
Put(Item=>Sin_Result, Fore=>1, Aft=>4, Exp=>0);

end sin;

Integer? float? confused...

[WM]

I have written a program to calculate Sin. The compiler(AdaGIDE 6.23) said:
"expected type standard.float", why? Please piont out errors, Thanks.

with Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
use Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;

procedure sin is
   sin_result : float;
   i : integer;
   function Calc_Sin (Num : Integer) return float is
      begin
         Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;
         return Sin_Result;
   end Calc_Sin;

begin

put("input int: ");
get(i);
Sin_Result := Calc_Sin(Num=>i);
Put(Item=>Sin_Result, Fore=>1, Aft=>4, Exp=>0);

end sin;

Integer? float? confused...

[WM]

I have written a program to calculate Sin. The compiler(AdaGIDE 6.23) said:
"expected type standard.float", why? Please piont out errors, Thanks.

with Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
use Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;

procedure sin is
   sin_result : float;
   i : integer;
   function Calc_Sin (Num : Integer) return float is
      begin
         Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;
         return Sin_Result;
   end Calc_Sin;

begin

put("input int: ");
get(i);
Sin_Result := Calc_Sin(Num=>i);
Put(Item=>Sin_Result, Fore=>1, Aft=>4, Exp=>0);

end sin;

Re: Integer? float? confused...

[chris.danx]

You need to use 3.0, 6.0, 5.0 and 120.0 in function Calc_Sin.  This is
because Ada requires a float to have decimal point in it somewhere.  If you
don't include the .0 Ada thinks it's an integer.  Also convert the Num to a
float by Float(Num) otherwise Ada thinks Num is an integer -- which it is!
but your can't mix types so you've got to convert.

May i make a suggestion?  It would be better to have

function Calc_Sin (Num : integer) return float is
begin
    return Num - (Num ** 3) / 6 + (Num ** 5) / 120;
end Calc_Sin

instead of using sin_result.  This variable is global and in other programs
you might do something similar and it'll screw everything up.  You could
move the declaration of Sin_Result inside the function and what you've
written would work if you fixed the type conversion problem.  I haven't
fixed it in the above function cos' that's for you to do.



Hope this helps,
Chris Campbell

p.s. let me know *when* you get it working, or if anythings not clear -- i'm
terrible at explaining things to people.

Re: Integer? float? confused...

[EtienneB]

>          Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;
>          return Sin_Result;

Num - (Num ** 3) / 6 + (Num ** 5) / 120;
this expression is integer and your function must return float
    I advice you to change num type to float and to return

Num - (Num ** 3) / 6.0 + (Num ** 5) / 120.0;

But sin(x) is already defined in ada.numerics.aux
Voila
Etienne Baudin

Re: Integer? float? confused...

[Ken Garlington]

I ran this program through AdaGIDE v 6.26, and it gave me one other piece of
information: the line and column number where the error occurred. (I'm
pretty sure that AdaGIDE v 6.23 does the same.) I've annotated your source
code, see below...

"WM" <wwminirl@hotmail.com> wrote in message
news:998i7d$19j21@tech.port.ac.uk...
: I have written a program to calculate Sin. The compiler(AdaGIDE 6.23)
said:
: "expected type standard.float", why? Please piont out errors, Thanks.
:
: with Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
: use Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
:
: procedure sin is
:    sin_result : float;
:    i : integer;
:    function Calc_Sin (Num : Integer) return float is
:       begin
:          Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;

*** The problem appears to be in the line above. Sin_Result is of type
standard.float, so that appears to be OK. I wonder what the type is of the
stuff on the right hand side of the assignment statement?

:          return Sin_Result;
:    end Calc_Sin;
:
: begin
:
: put("input int: ");
: get(i);
: Sin_Result := Calc_Sin(Num=>i);
: Put(Item=>Sin_Result, Fore=>1, Aft=>4, Exp=>0);
:
: end sin;
:
:

Re: Integer? float? confused...

[Sven Nilsson]

The problem is the line

 Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;

where you have a lot of integer arithmetic and expect a float in the
end. If you write it like this:

 Sin_Result := float(Num) - float(Num ** 3.0) / 6.0 + float(Num **
5)/120.0;

That should work. Now we've upcasted all the integers to floats and
perform only float arithmetic, which means that the end result is a
float as well.

-Sven

Re: Integer? float? confused...

[dis00109]

WM wrote:

> I have written a program to calculate Sin. The compiler(AdaGIDE 6.23) said:
> "expected type standard.float", why? Please piont out errors, Thanks.
>
> with Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
> use Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
>
> procedure sin is
>    sin_result : float;
>    i : integer;
>    function Calc_Sin (Num : Integer) return float is
>       begin
>          Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;
>          return Sin_Result;
>    end Calc_Sin;
>
> begin
>
> put("input int: ");
> get(i);
> Sin_Result := Calc_Sin(Num=>i);
> Put(Item=>Sin_Result, Fore=>1, Aft=>4, Exp=>0);
>
> end sin;

Your problem is that you have correctly defined the result as a float
(Sin_Result:Float) however you need to convert the data from an integer to a
float as you perform the function on it. This mean that instead of writing:

Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;

you want to be writing:

Sin_Result:=Float(Num - (Num ** 3) / 6 + (Num ** 5) / 120);

This will solve your problem however don't forget to convert the integer to
radians before applying Sine to them (1 degree = pi / 180 therefore 90 degrees
= 1.57 radians).

Re: Integer? float? confused...

[mark]

A reason for you experencing this error is that the computer is finding a 
integer and not a Float.

 A Float is a number with a decimal point in it e.g. 16.00 or 0.67 etc
 A integer is a number that is exact e.g. 1,2,3,4,5, 16 etc

 The fact that you have said that "Num" is an integer when it is then 
stated that it is Float make the machine confused. 
Try making "Num" a Float and that should clear up the error message!!


 Good luck


WM wrote:
> 
> 
> I have written a program to calculate Sin. The compiler(AdaGIDE 6.23) 
said:
> "expected type standard.float", why? Please piont out errors, Thanks.
> 
> with Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
> use Ada.Text_Io, Ada.Integer_Text_Io,Ada.Float_Text_Io;
> 
> procedure sin is
>    sin_result : float;
>    i : integer;
>    function Calc_Sin (Num : Integer) return float is
>       begin
>          Sin_Result := Num - (Num ** 3) / 6 + (Num ** 5) / 120;
>          return Sin_Result;
>    end Calc_Sin;
> 
> REMOVED INCLUDED FILE sin;
> 
> 


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