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std::setprecision(3)	      C++ Standard Libary	  std::setprecision(3)

NAME
       std::setprecision - std::setprecision

Synopsis
	  Defined in header <iomanip>
	  /*unspecified*/ setprecision(	int n );

	  When used in an expression out << setprecision(n) or in >> setpreci-
       sion(n),	sets the
	  precision parameter of the stream out	or in to exactly n.

Parameters
	  n - new value	for precision

Return value
	  Returns  an  object of unspecified type such that if str is the name
       of an output
	  stream of type std::basic_ostream<CharT, Traits> or an input	stream
       of type
	  std::basic_istream<CharT,  Traits>,  then the	expression str << set-
       precision(n) or str
	  >> setprecision(n) behaves as	if the following code was executed:

	  str.precision(n);

Example
       // Run this code

	#include <iostream>
	#include <iomanip>
	#include <cmath>
	#include <limits>
	int main()
	{
	    const long double pi = std::acos(-1.L);
	    std::cout << "default precision (6): " << pi << '\n'
		      << "std::setprecision(10): " << std::setprecision(10) <<
       pi << '\n'
		      << "max precision:	 "
		      <<    std::setprecision(std::numeric_limits<long	  dou-
       ble>::digits10 +	1)
		      << pi << '\n';
	}

Output:
	default	precision (6): 3.14159
	std::setprecision(10): 3.141592654
	max precision:	       3.141592653589793239

See also
	  fixed
	  scientific
	  hexfloat     changes formatting used for floating-point I/O
	  defaultfloat (function)
	  (C++11)
	  (C++11)
	  precision    manages decimal precision of floating point operations
		       (public member function of std::ios_base)

http://cppreference.com		  2022.07.31		  std::setprecision(3)

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