# 07.26.07

## Exercise 4.2

From the text:

intToFloat :: Int -> Float intToFloat i = fromInteger (toInteger i) |

The exercise:

pixelToInch :: Int -> Float pixelToInch x = intToFloat x / 100 {- pixelToInchBad :: Int -> Float pixelToInchBad x = intToFloat (x / 100) -} pixelToInchBad :: Int -> Float pixelToInchBad x = intToFloat (x `div` 100) |

Apart from anything else, the commented out version of `pixelToInchBad` gives an error, viz.: `Instance of Fractional Int required for definition of pixelToInchBad`. Assuming the second version is what the book is hinting at, this has the same issues with loss of precision that we saw in Exercise 4.1.

Edit: this is indeed what the book should properly say (see erratum 4).