create a byte a byte array from a double value

[stonee74]

Hi Guys,
I am currently developing a Client/Server program in Java. The server I try to understand sends somewhat unsigned double values whereas in JAVA only signed doubles do exist.
However, can anybody give my an idea how to generate in C(++) a byte array from any double value to the console in order to find a suitable algorithm for my app.

any help is greatly appreciated!

regards,
stonee

 

[mlb321]

Try this:

double d;
byte* p = (byte*)&d;

for (i=0; i<sizeof(double); i++)
printf(&quot;0x02x &quot;, *(b+i) );
printf(&quot;\n&quot;

 

[stonee74]

I found a way by myself, thanks anyway..
stone

main (int argc, char* argv[])
{
;
double d;

unsigned char* b1 = (unsigned char*)&d;
char* b2 = (char*)&d;


while(1)
{
printf(&quot;double?: \n&quot;
scanf(&quot;%g&quot;,&d);

for (int i=0; i<sizeof(d); i++)
{
printf(&quot;byte: %i, signed int %i,unsigned int %i&quot;, (i),*(b1+i),*(b2+i) );
printf(&quot;\n&quot;
}
}

}

 

[stonee74]

ehmmm once again:
is this correct what i did?
Does anybody know the correct specification of a floating point number in IEE754?
Is the composition a such a double in C++ and Java the same?
obviously not...

thanks for any ideas,
stonee

 

[mlb321]

try these places:

http://http.cs.berkeley.edu/~wkahan/ieee754status/IEEE754.PDF

http://cch.loria.fr/documentation/IEEE754/wkahan/JAVAhurt.pdf