Conversion of integer to float ?? in Haskell

[neokewl]

Hey

I was trying out a program to find the area of cirlce in Haskell. I have a problem in converting the data types from integer to float.
The pgm is as follows:

type Point = (Int,Int)

data Fig = Pt Point
| Circle Point Int

area :: Fig -> Float
area (Circle a b) = 3.141 * b*b

the above definition of area of circle is giving me compile errors as 3.141 is a fractional value.

How do i convert the integer value of b to floating point so tht the multiplication is compatible.

thnx
neokewl

[Clayton]

Is it necessary that 'b' be the type of Integer?

Also, next time please use [code][/code] tags

[neokewl]

yes b is of type integer as the constructor Circle takes a Point and Int as arguments...

yea next time i will put code tags ... sorry 4 tht...

[Clayton]

That's the point I'm trying to make though, why not just have your Point have two Floats, and then have the Circle constructor take the point, and a Float?

[neokewl]

yes.. it works fine if we define point as

type Point = (Float,Float) ...

thts the easy way out ....

i want to figure out how to do type conversion in haskell ....
sometimes the data one gets may not be as we require it ....

[Clayton]

well in this sort of application, Floats actually make more sense, because the following is a perfectly legal ordered pair (or point) (1.2, 5.3) and the radius of your circle isn't always going to be an integer.

[neokewl]

yes ..i agree with u tht floats make more sense ....

but given a situation where u are given int... isnt there a way for type conversion in haskell....

my aim is not to find the area of the circle or rectangle , but it is to understand type conversion in haskell ....

its just some problem i formulated myself ..... to do this...

[wtd]

Perhaps the fromInteger function?

[neokewl]

Hi,

The fromInteger function works fine for Integer type to float type. Thnx buddy.


Cheers
neokewl