Date: Sat, 19 Nov 1994 15:53:26 -0500
From: davis AT amy DOT tch DOT harvard DOT edu ("John E. Davis")
To: turnbull AT shako DOT sk DOT tsukuba DOT ac DOT jp
Subject: RE: printf or floating point error?????
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu, dolan AT fnoc DOT navy DOT mil, gordon AT spot DOT colorado DOT edu

>   Consider:
>
>      float x, y;
>      long i = 10;
>
>      /* assume sizeof (float) == sizeof (long) */
>
>      x = (float) i;
>      y = *(float *) &i;
>
>   Here `x' will have the value of 10.0 whereas `y' has the bit
>   pattern that you re suggesting above.  `y' will will almost
>   certainly not be 10.0 and `x' will not have the bit pattern of `i'.
>   That is, the float cast above will definitely modify the bit
>   pattern of i.
>
>This example is bogus because
>
>      x = i;
>
>will work without the cast, and it means (in K&R C)
>
>      x = (float) (double) i;

Just because I used an explicit cast in the conversion of int to float does
not make the example bogus.   I think the example illustrates the point
quite well, in fact, I believe that it would not be as effective without the
cast.

--John