std::ios_base::precision - cppreference.com (original) (raw)

| 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

[edit] Return value

The precision before the call to the function

[edit] Example

#include   int main() { const double d = 12.345678901234; std::cout << "The default precision is " << std::cout.precision() << "\n\n"; std::cout << "With default precision d is " << d << '\n'; std::cout.precision(8); std::cout << "With high precision d is " << d << '\n'; }

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.

[edit] See also