Re: [Dev-C++] POW question

[Per W. <pw...@ia...>]

2 raised to 8 is 256. Dividing by two is 128. 128+1 is 129.

Your compiler don't do wrong. You have to know what _you_ want before
putting requirements on the compiler.

The easiest way to get 128.5 is:
a = 128.5.

If you want a formula to evaluate to 128.5 for a specific variable value,
you have to explain what the formula should evaluate to reach the value
128.5 (or possibly -128.5).

/Per W

On Mon, 27 Jun 2005, Scott wrote:

> >I'm not sure how abs() would help.. unless that's to ensure that the
> >original value is positive before multiplying by negative one?
> >-Lukas
>
> This is still not working right,
> Iv'e been scratching my head on this all day..
>
> I'm trying to get the value of 128.5
> But instead all the mentioned formula's are giving me 129...
>
> What i'm trying to express is this..
>
> (2^8+1)/ 2 = 128.5
>
> So in C/C++ it should be pow(2,8)/2+1  (However it returns 129)
>
> Here is a quick test....
> ----------------------------------------------------------
> #include <stdio.h>
> #include <math.h>
> void main()
> {
> double test;
> test=pow(2,8)/2+1; //figure 2 to the eighth power +1
> printf("The number is %0.0f \n",test);
> system("PAUSE");
> return 0;
> }
> -----------------------------------------------------------
> #include <stdio.h>
> #include <math.h>
> void main()
> {
> float test;
> test=((2^8+1) / 2); //figure 2 to the eighth power +1
> printf("The number is %0.0f \n",test);
> system("PAUSE");
> return 0;
> }
> -------------------------------------------------------------
>
> Here is a quick snippett from the actual source code i'm using to position
> points.
>
> sprintf( cmd, "MAKEBOX <%g %g %g> <%g %g %f> <%d %d %d>",
>       -128.5, -0.0, -128.5,  pow(2,8)/2+1, 0.0, pow(2,8)/2+1, 1, 1, 1 );
>    local->evaluate( local->data, cmd );
>
> Both suffer from the returning the same 129 figure....
> I must be missing something stupid...  (i'll try again in the morning)
>
> Thanks for the help guys..
>
> Cheers,
> Scott.
>
>
>
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