std::ios_base:: precision

Manages the precision (i.e. how many digits are generated) of floating point output performed by std::num_put::do_put .

The default precision, as established by std::basic_ios::init , is 6.

Parameters

Return value

The precision before the call to the function

Example

#include <iostream>
 
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';
}

The  default precision is 6
 
With default precision d is 12.3457
With high    precision d is 12.345679

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also