std::ios_base::precision (3) - Linux Manuals

std::ios_base::precision: std::ios_base::precision

NAME

std::ios_base::precision - std::ios_base::precision

Synopsis

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.

Parameters

new_precision - new precision setting

Return value

the precision before the call to the function

Example

// Run this code

  #include <iostream>
  int main()
  {
      const double d = 1.2345678901234;
      std::cout << "The default precision is " << std::cout.precision() << "\n\n";
      std::cout << "With default precision d is " << d << '\n';
      std::cout.precision(12);
      std::cout << "With high precision d is " << d << '\n';
  }

Output:

  The default precision is 6

  With default precision d is 1.23457
  With high precision d is 1.23456789012