std::ios_base::precision
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streamsize precision() const;
(1)
streamsize precision( streamsize new_precision );
(2)
Manages the precision (i.e. how many digits are generated) of floating point output performed by std::num_put::do_put .
1) Returns the current precision.
2) Sets the precision to the given one. Returns the previous precision.
The default precision, as established by std::basic_ios::init , is 6.
[edit] Parameters
new_precision
-
new precision setting
[edit] Return value
The precision before the call to the function
[edit] Example
Run this code
Output:
The default precision is 6 With default precision d is 12.3457 With high precision d is 12.345679
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 189 | C++98 | 'precision' was defined as 'the number of digits after the decimal point', but it is not correct in some cases |
corrected |