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std::ios_base::precision(3)    C++ Standard Libary   std::ios_base::precision(3)

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 = 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

	Defect reports

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

	  DR	Applied to		Behavior as published		    Cor-
     rect behavior
			   'precision' was defined as 'the number of digits
	LWG 189 C++98	   after					    cor-
     rected
			   the decimal point', but it is not correct in
			   some cases

See also
	width	     manages field width
		     (public member function)
	setprecision changes floating-point precision
		     (function)

http://cppreference.com 	   2024.06.10	     std::ios_base::precision(3)
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