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

NAME
     std::setbase - std::setbase

Synopsis
	Defined in header <iomanip>
	/*unspecified*/ setbase( int base );

	Sets  the  numeric base of the stream. When used in an expression out <<
     setbase(base)
	or in >> setbase(base), changes the basefield flag of the stream out  or
     in,
	depending on the value of base:

	  * the value 16 sets basefield to std::ios_base::hex.
	  * the value 8 sets std::ios_base::oct.
	  * the value 10 sets std::ios_base::dec.

	Values	of  base  other than 8, 10, or 16 reset basefield to zero, which
     corresponds to
	decimal output and prefix-dependent input.

Parameters
	base - new value for basefield

Return value
	An object of unspecified type such that

	  * if out is an object of type std::basic_ostream<CharT,  Traits>,  the
     expression
	    out << setbase(base)
	       * has type std::basic_ostream<CharT, Traits>&
	       * has value out
	       * behaves as if it called f(out, base)
	  *  if  in  is an object of type std::basic_istream<CharT, Traits>, the
     expression in
	    >> setbase(base)
	       * has type std::basic_istream<CharT, Traits>&
	       * has value in
	       * behaves as if it called f(in, base)

	where the function f is defined as:

      void f(std::ios_base& str, int base)
      {
	  // set basefield
	  str.setf(base == 8 ? std::ios_base::oct :
	      base == 10 ? std::ios_base::dec :
	      base == 16 ? std::ios_base::hex :
	      std::ios_base::fmtflags(0), std::ios_base::basefield);
      }

Example
     // Run this code

      #include <iomanip>
      #include <iostream>
      #include <sstream>

      int main()
      {
	  std::cout << "Parsing string \"10 0x10 010\"\n";

	  int n1, n2, n3;
	  std::istringstream s("10 0x10 010");

	  s >> std::setbase(16) >> n1 >> n2 >> n3;
	  std::cout << "hexadecimal parse: " << n1 << ' ' << n2 << ' ' << n3  <<
     '\n';

	  s.clear();
	  s.seekg(0);

	  s >> std::setbase(0) >> n1 >> n2 >> n3;
	  std::cout  <<  "prefix-dependent parse: " << n1 << ' ' << n2 << ' ' <<
     n3 << '\n';

	  std::cout << "hex output: " << std::setbase(16)
		    << std::showbase << n1 << ' ' << n2 << ' ' << n3 << '\n';
      }

Output:
      Parsing string "10 0x10 010"
      hexadecimal parse: 16 16 16
      prefix-dependent parse: 10 16 8
      hex output: 0xa 0x10 0x8

	Defect reports

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

	  DR	 Applied  to	      Behavior as published	     Correct be-
     havior
	LWG 183 C++98	   setbase could only be used with streams  usable  with
     any
			   of  type  std::ostream  or  std::istream    character
     stream

See also
	dec	   changes the base used for integer I/O
	hex	   (function)
	oct
	showbase   controls whether prefix is used to indicate numeric base
	noshowbase (function)

http://cppreference.com 	   2024.06.10			 std::setbase(3)
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