Why output of cout << setprecision(2) << 0.999 is 1 instead of 1.0?

Question

The significant digits is 2.

Why the output of

cout << setprecision(2) << 0.999 << endl;`

is 1 instead of 1.0?

I hope answer below addresses your issue. Please accept his answer if it works to close it! — Failed Scientist, Jun 22 '16 at 09:32
Isn't the real question here, why it is printing `1.0` instead of `0.9`? — , Jun 22 '16 at 10:19
Ah, my own question is answered here: https://stackoverflow.com/questions/10922366/does-setprecision-in-c-round-if-so-why-am-i-seeing-this — , Jun 22 '16 at 10:26

score 5 · Accepted Answer · edited Jun 22 '16 at 09:50

5

The default formatting does not print trailing zeros; you need to set the floating point formatting to fixed, see also this reference. So what you need is

cout << setprecision(2) << fixed << 0.999 << endl;

Note also that setprecision refers to the decimal digits, so for 1.0 you would need setprecision(1)

edited Jun 22 '16 at 09:50

Karl Nicoll

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answered Jun 22 '16 at 09:20

dennis

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Why output of cout << setprecision(2) << 0.999 is 1 instead of 1.0?

1 Answers1