#include <stdio.h>
#include <math.h>
int main()
{
double a= 10.0;
double b= 1e+308;
printf("%dn",isinf(a * b));
return 0;
}
Prints 1 on: 64bit intel, 32bit PowerPC, 32bit SPARC, 64bit Sparc. But prints zero on 32bit intel.
Oh, but if you build that with g++ instead of gcc on 32bit Intel, you get 1.
Tags: floating point, fpu, gcc
Ergh. I read another fun example of that just this afternoon in this C++ FAQ
http://www.parashift.com/c++-faq-lite/newbie.html#faq-29.18
On my i386 system at least, the following does in fact print “Huh?!?”. I really really appreciate integers.
#include
void foo(double x, double y)
{
if (cos(x) != cos(y)) {
std::cout << “Huh?!?\n”;
}
}
int main()
{
foo(1.0, 1.0);
return 0;
}