[llvm-dev] [question] с-double: 35.7 * 100 vs 3570.0

[Daniil Troshkov via llvm-dev]

Hi all!

There is a simple c code:

double a = 3570.0;
double b = 35.7 * 100;
int main ()
{
  if (b != a) return 1;
  return 0;
}

It returns 1 due to:
40abe400 00000000 //a = 3570.0
40abe400 00000001 //b = 35.7 * 100;

gcc do the same thing, so I think it's ok but why?

For floats:

float a = 3570.0;
float b = 35.7 * 100;
int main ()
{
  if (b != a) return 1;
  return 0;
}

It returns 0...
455f2000 //a = 3570.0
455f2000 //b = 35.7 * 100;

I will be grateful to get any explanations.
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