c++ double rounding problems

Question

Why?

11979999 / 10000 = 1197.999877930

With

printf("%f\n", static_cast<double>(((float)11979999 / (float)10000)));

Instead of

1197.9999

And how to fix it?

Possible duplicate of [Is floating point math broken?](http://stackoverflow.com/questions/588004/is-floating-point-math-broken) — Dan Lowe, Oct 30 '15 at 00:09

score 3 · Accepted Answer · answered Oct 29 '15 at 23:51

3

In your code you did the calculation in single precision, then you converted the result to double. If you want double precision, do the calculation in double precision:

  printf("%f\n", (double)11979999 / (double)10000);

answered Oct 29 '15 at 23:51

A.S.H

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perfect! 1197.999900 is the output now. – PeeS Oct 29 '15 at 23:52

c++ double rounding problems

1 Answers1